Novel mutated lactonase enzymes, compositions containing them and uses thereof

Abstract

The present invention relates to novel mutated lactonases, to their uses as well as to compositions containing them.

Description

[0001] NOVEL MUTATED LACTONASE ENZYMES, COMPOSITIONS CONTAINING THEM AND THEIR USES The present invention relates to novel mutated lactonases, their uses as well as compositions containing them. Certain bacteria use a molecular communication system called Quorum Sensing (QS) to coordinate numerous biological functions such as virulence or biofilm formation. They notably use acyl-homoserine lactones (AHLs) as communication molecules. Enzymes of the phosphotriesterase-like lactonase (PLL) family exhibit both phosphotriesterase activity and lactonase activity and are capable of hydrolyzing homoserine lactones, involved in bacterial QS, with varying degrees of efficiency. Since bacterial biofilm formation leads to medical and environmental problems, it is important to find solutions to effectively eliminate bacterial biofilms.Thus, in a first aspect, the invention relates to novel mutated lactonases. In a second aspect, the invention relates to the use of said mutated lactonases. In a third aspect, the invention relates to compositions comprising said mutated lactonases. In a fourth aspect, the invention relates to a method for preventing and / or treating pathologies linked to bacterial infections. Surprisingly, the inventors of the present application have shown that one or more mutations in the sequence of the lactonase enzymes significantly increase the effectiveness of the lactonases towards the AHLs involved in bacterial QS. In all aspects of the present invention, said mutated lactonase enzyme is derived from the hyperthermophilic lactonase of Saccharolobus solfataricus (SsoPox), Sulfolobus acidocalaricus, Sulfolobus islandicus or Saccharolobus shibatae belonging to the family of phosphotriesterase-like lactonases.Thus, in a first aspect, the invention relates to novel mutated lactonases. In particular, the inventors of the present application have identified that the mutation of an amino acid X in the consensus sequence of a wild-type lactonase consisting of: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID NO: 1) and that at least one mutation of an amino acid X. a -X j of loop 8 of phosphotriesterase-like lactonases consisting of: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), made it possible to obtain a mutated lactonase having an increased hydrolysis activity on homoserine lactone substrates compared to said wild-type lactonase. In the present invention, the expression ''an increased lactonase hydrolysis activity'' means that, for the hydrolysis of a homoserine lactone substrate, the mutated lactonase according to the invention has a value of the Kcat / K ratio M higher compared to the value of the Kcat / K ratio Mof the unmutated lactone from which it is derived. To obtain the kcat and KM values, the enzymatic hydrolysis of the lactones was monitored over time. The hydrolytic opening of the lactone ring results in the release of an acid function, thus the parameters are determined by following the acidification of the reaction medium. The measurement was carried out in a buffer (2.5 mM bicine pH 8.3, 150 mM NaCl, 0.2 mM CoCl2,0.25 mM cresol violet and 0.5% DMSO). Cresol violet is a pH indicator used to monitor the acidification of the medium caused by the hydrolysis of the lactone ring. The hydrolysis monitoring is carried out by measuring the variation in the absorbance of the reaction medium at λ = 577 nm for 10 minutes. Each point was carried out in triplicate and the Gen5.1 software was used to evaluate the initial degradation rate at each substrate concentration. The kcat and KM values ​​were obtained using a regression of the Michaelis-Menten equation with the GraphPad Prism 7 software. Thus, in a first embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, said mutated lactonase comprising -a first mutation by substitution of an amino acid in a first consensus sequence SEQ ID NO: 1 of a wild-type lactonase,which first consensus sequence in said wild-type lactonase is represented by SEQ ID: 1: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID: 1) X represents the amino acid V, which first consensus sequence in said mutated lactonase is represented by SEQ ID NO: 2: IRF-[M / S]-E-[K / R]-X1-VK-[A / T / E]-TGIN (SEQ ID NO: 2) X1 represents the substituted amino acid selected from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A or I, -at least one other mutation by substitution of an amino acid in a second consensus sequence of the wild-type lactonase represented by SEQ ID: 3: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), Xa is selected from the group consisting of W, T, A, F, V, I, M and L, Xb represents amino acid A, Xc is selected from the group consisting of Y and L, Xd represents amino acid K, Xe represents amino acid P, Xf represents amino acid K,Xg represents amino acid L, Xh represents amino acid A, Xi is selected from the group consisting of R and K, Xj represents amino acid S, which second consensus sequence in said substitution-mutated lactonase is represented by SEQ ID: 4: X2-G-[T / I]-X3-[K / R]-PE-X4-X5-X6-X7-X8-X9-PX, 10 -WX 11 (SEQ ID NO: 4) at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11being substituted, said mutated lactonase having an increased lactonase activity compared to said wild-type lactonase, preferably on at least one substrate. The inventors of the present application have also shown that these mutations make it possible to obtain a mutated lactonase having a greatly improved hydrolysis activity on homoserine lactone substrates compared to said wild-type lactonase, making it possible to change the specificity spectrum of the lactonases and / or to increase the activity with respect to homoserine lactone substrates. In a particular embodiment, the invention relates to a mutated lactonase as described above having an increased lactonase activity compared to said wild-type lactonase on at least one substrate chosen from: C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL and 3-oxo-C8-HSL. These substrates are homoserine lactones and are found in quorum sensing,allowing bacteria to communicate. The expression "significantly improved hydrolysis activity" means herein that the mutated lactonases as defined above have up to 297 times greater hydrolysis activity on homoserine lactone substrates compared to said wild-type lactonase. In another embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, said mutated lactonase comprising -a first mutation by substitution of an amino acid in a first consensus sequence SEQ ID NO: 1 of a wild-type lactonase, which first consensus sequence in said wild-type lactonase is represented by SEQ ID: 1: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID: 1) X represents the amino acid V,which first consensus sequence in said mutated lactonase is represented by SEQ ID NO: 2: IRF-[M / S]-E-[K / R]-X1-VK-[A / T / E]-TGIN (SEQ ID NO: 2) X1 represents the substituted amino acid selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A or I, -at least one other mutation by substitution of an amino acid in a second consensus sequence of the wild-type lactonase represented by SEQ ID: 3: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), Xa is selected from the group consisting of W, T, A, F, V, I, M and L, Xb represents amino acid A, Xc is selected from the group consisting of Y and L, Xd represents amino acid K, Xe represents amino acid P, Xf represents amino acid K, Xg represents amino acid L, Xh represents amino acid A, Xi is selected from the group consisting of R and K, Xj represents amino acid S,which second consensus sequence in said substitution-mutated lactonase is represented by SEQ ID:4: X2-G-[T / I]-X3-[K / R]-PE-X4-X5-X6-X7-X8-X9-PX, 10 -WX 11 (SEQ ID NO: 4) at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11being substituted, X2is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A, X3is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C, in particular G, I, M, and V, in particular G, X4is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular F, X5is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular L, X6is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, W, Y, and C, in particular L, X7is selected from the group consisting of polar amino acids S, T, N, Q, E, D, R, and H, especially N, X8 is selected from the group consisting of the hydrophobic amino acids V, I, M, F, G, A, P, W, Y, and C, especially V, X9 is selected from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C,including G, M and W, X, 10 is selected from the group consisting of non-bulky amino acids G, P, L, I, A, D, C, S, T, and N, including A, X 11is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, said mutated lactonase having an increased lactonase activity compared to said wild-type lactonase, preferably on at least one substrate. In a particular embodiment, X1 is the amino acid Isoleucine I. In a particular embodiment, the invention relates to a mutated lactonase as described above, in which X1 is amino acid I and said substrate is selected from: C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL and 3-oxo-C12-HSL. In another embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, said mutated lactonase comprising -a first mutation by substitution of an amino acid in a first consensus sequence SEQ ID NO: 1 of a wild-type lactonase,which first consensus sequence in said wild-type lactonase is represented by SEQ ID: 1: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID: 1) X represents the amino acid V, which first consensus sequence in said mutated lactonase is represented by SEQ ID NO: 2: IRF-[M / S]-E-[K / R]-X1-VK-[A / T / E]-TGIN (SEQ ID NO: 2) X1 represents the substituted amino acid selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A or I, -at least one other mutation by substitution of an amino acid in a second consensus sequence of the wild-type lactonase represented by SEQ ID: 3: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), Xa is selected from the group consisting of W, T, A, F, V, I, M and L, Xb represents amino acid A, Xc is selected from the group consisting of Y and L, Xd represents amino acid K, Xe represents amino acid P, Xf represents amino acid K,Xg represents amino acid L, Xh represents amino acid A, Xi is selected from the group consisting of R and K, Xj represents amino acid S, which second consensus sequence in said substitution-mutated lactonase is represented by SEQ ID:4: X2-G-[T / I]-X3-[K / R]-PE-X4-X5-X6-X7-X8-X9-PX, 10 -WX 11 (SEQ ID NO: 4) at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11 being substituted, X2is selected from the group consisting of A and I, X3is selected from the group consisting of V, I, M, G, and T, X4represents F, X5represents L, X6represents L, X7represents N, X8represents V, X9is selected from the group consisting of F, M, G, Y, C, and W, X 10 represents A, X 11represents A. said mutated lactonase having increased lactonase activity compared to said wild-type lactonase, preferably on at least one substrate. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X2 of the sequence SEQ ID: 4 of the mutated lactonase, X2 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X3 of the sequence SEQ ID: 4 of the mutated lactonase, X3 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C, in particular G, I, M, T, and V, in particular G.In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X4 of the sequence SEQ ID: 4 of the mutated lactonase, X4 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular F. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X5 of the sequence SEQ ID: 4 of the mutated lactonase, X5 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular L.In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X6 of the sequence SEQ ID: 4 of the mutated lactonase, X6 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, W, Y, and C, in particular L. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X7 of the sequence SEQ ID: 4 of the mutated lactonase, X7 is chosen from the group consisting of the polar amino acids S, T, N, Q, E, D, R, and H, in particular N.In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X8 of the sequence SEQ ID: 4 of the mutated lactonase, X8 is chosen from the group consisting of the hydrophobic amino acids V, I, M, F, G, A, P, W, Y, and C, in particular V. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X9 of the sequence SEQ ID: 4 of the mutated lactonase, X9 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C, in particular G, M and W. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 relates to amino acid X. 10of the sequence SEQ ID: 4 of the mutated lactonase, X 10 is selected from the group consisting of non-bulky amino acids G, P, L, I, A, D, C, S, T, and N, including A. In a particular embodiment, the at least one other mutation by substitution of an amino acid in the consensus sequence of the wild-type lactonase represented by SEQ ID: 3 concerns the amino acid X 11 of the sequence SEQ ID: 4 of the mutated lactonase, X 11is selected from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A. In another embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, said mutated lactonase comprising -a first mutation by substitution of an amino acid in a first consensus sequence SEQ ID NO: 1 of a wild-type lactonase, which first consensus sequence in said wild-type lactonase is represented by SEQ ID: 1: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID: 1) X represents amino acid V, which first consensus sequence in said mutated lactonase is represented by SEQ ID NO: 2: IRF-[M / S]-E-[K / R]-X1-VK-[A / T / E]-TGIN (SEQ ID NO: 2) X1 represents amino acid I,-at least one further mutation by substitution of an amino acid in a second consensus sequence of the wild-type lactonase represented by SEQ ID: 3: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), Xa is selected from the group consisting of W, T, A, F, V, I, M and L, Xb represents amino acid A, Xc is selected from the group consisting of Y and L, Xd represents amino acid K, Xe represents amino acid P, Xf represents amino acid K, Xg represents amino acid L, Xh represents amino acid A, Xi is selected from the group consisting of R and K, Xj represents amino acid S, which second consensus sequence in said lactonase mutated by substitution is represented by SEQ ID: 4: X2-G-[T / I]-X3-[K / R]-PE-X4-X5-X6-X7-X8-X9-PX, 10 -WX 11 (SEQ ID NO: 4) at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11being substituted, X2is selected from the group consisting of A and I, X3is selected from the group consisting of V, I, M, G, and T, X4represents F, X5represents L, X6represents L, X7represents N, X8represents V, X9is selected from the group consisting of F, M, G, Y, C, and W, X 10 represents A, X 11 represents A. said mutated lactonase having an increased lactonase activity compared to said wild-type lactonase, preferably on at least one substrate. In another preferred embodiment, the invention relates to a mutated lactonase belonging to the family of phosphotriesterase-like hypertermophilic lactonases represented by the sequence SEQ ID NO: 4 in which a single mutation by substitution concerns one of the amino acids chosen from the group consisting of X2, X3, X4, X5, X6, X7, X8, X9, X 10 and X 11. In another preferred embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases represented by the sequence SEQ ID NO: 4 in which at least two substitution mutations concern at least two of the amino acids selected from the group consisting of X2, X3, X4, X5, X6, X7, X8, X9, X 10 and X 11. In another embodiment, the invention relates to a mutated lactonase belonging to the family of hyperthermophilic phosphotriesterase-like lactonases in which the at least one other substitution mutation concerns amino acids X3, and X9, of the sequence SEQ ID: 4 in which: X3 is selected from the group consisting of I, and G, X9 is selected from the group consisting of F, M, Y and C. Table 1 below summarizes the particularly preferred mutations described in this second embodiment of this first aspect. These mutations are made in the second consensus sequence (SEQ ID NO: 3) of the wild-type lactonase and make it possible to obtain the mutated lactonases described in this second embodiment of this first aspect. In another embodiment, the invention relates to a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases in which said mutated lactonase has a sequence identity of at least 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% with the sequences SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, and SEQ ID NO: 47, provided that said mutated lactonase retains increased lactonase activity compared to said wild-type lactonase.In this particular embodiment, it is understood that any variation in the sequence of said mutated lactonase leading to a sequence identity of at least 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% with the sequences SEQ ID NO: 26 to SEQ ID NO: 47 concerns all positions other than those of amino acid X in the consensus sequence of a wild-type lactonase consisting of: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID NO: 1) and amino acids Xa-Xj of loop 8 of phosphotriesterase-like lactonases consisting of: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: : 3).For example, a mutated lactonase that has 98% identity with the sequence SEQ ID NO: 26 which corresponds to the mutant SsoPox V82I / W263A, may have 1 to 6 other mutations among 303 possible positions out of 314 amino acids of the sequence SEQ ID NO: 26, it being understood that the positions X and Xa-Xj of the consensus sequences SEQ ID NO: 1 and SEQ ID NO: 3 must correspond to the different embodiments according to the present invention. In all the embodiments previously described, said substrate can be chosen from: C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL and 3-oxo-C8-HSL. These substrates are homoserine lactones found in quorum sensing, allowing bacteria to communicate. In all aspects of the present invention, said wild lactonase may be selected from Saccharolobus solfataricus (SsoPox), Sulfolobus acidocalaricus, Sulfolobus islandicus and Saccharolobus shibatae.In all aspects of the present invention, and according to a particular embodiment of this first aspect, said wild-type lactonase is chosen from Saccharolobus solfataricus (SsoPox) of sequence SEQ ID NO: 5, Sulfolobus acidocalaricus of sequence SEQ ID NO: 6, Sulfolobus islandicus of sequence SEQ ID NO: 7 and Saccharolobus shibatae of sequence SEQ ID NO: 8. In all aspects of the present invention, said mutated lactonase has a lactonase activity increased by at least 2 times, preferably by 2 to 70 times, more preferably by 40 to 50 times, compared to said wild-type lactonase, on at least one substrate. In the present invention, the expression ''an increased lactonase hydrolysis activity'' means that, for the hydrolysis of a homoserine lactone substrate, the mutated lactonase according to the invention has a value of the Kcat / K ratio. M higher compared to the value of the Kcat / K ratio Mof the unmutated lactone from which it is derived. Thus, this means that the Kcat / K Mof the mutated lactonase according to the invention is increased by at least two times, preferably between 25 and 70 times and more preferably 40 to 50 times, compared to the non-mutated lactonase. In another embodiment, the invention relates to the use of a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, as described above, said mutated lactonase having an increased lactonase activity compared to said wild-type lactonase, in particular on at least one substrate, for: - disrupting the quorum-sensing of bacteria using homoserine lactone substrates to communicate, - limiting or inhibiting the formation of biofilms. In the present invention, the term "bacteria" designates a genus of prokaryotic microorganisms scientifically classified as such. Most bacteria can be classified as Gram-positive or Gram-negative bacteria. Thus, in a particular embodiment,the bacteria may be selected from gram-positive bacteria and gram-negative bacteria. According to the present invention, "gram-positive bacteria" are bacteria bound by a single lipid membrane and containing a thick layer of peptidoglycans (20 to 80 nm) which retains crystal violet staining in a Gram staining technique. According to the present invention, "gram-negative bacteria" are bacteria bound by a cytoplasmic membrane as well as an outer cell membrane, containing only a thin layer of peptidoglycans between the two membranes, which does not retain crystal violet dye in a Gram staining technique. More particularly, said bacteria may be selected from the group consisting of: Aeromonas sp., Aliivibrio sp., Edwardsiella sp., Enterobacter sp., Halomonas sp., Pantoea sp., Pseudomonas sp., Serratia sp., Vibrio sp., Acinetobacter sp., Agrobacterium sp.,Azospirillum sp., Burkholderia sp., Chromobacterium sp., Dickeya sp., Erwinia sp., Hafnia sp. Klebsiella sp., Methylobacterium sp., Pectobacterium sp., Ralstonia sp., Rhizobium sp., Sinorhizobium sp., Yersinia sp., Castellaniella sp., Dinoroseobacter sp., Gluconacetobacter sp., Mesorhizobium sp., Pandoraea sp., Proteus sp., Roseobacter sp., Nitrobacter sp., Rhodospirillum sp., Acidithiobacillus sp., Brucella sp., Kluyvera sp., Photobacterium sp., Rahnella sp. and Brayrhizobium sp. In another particular embodiment, the invention relates to a composition comprising as active ingredient at least one mutated lactonase as defined above. In a particular embodiment, said composition may also contain a pharmaceutically acceptable carrier. In a particular embodiment, said composition described above may be formulated with at least one excipient suitable for its use in the form of a solution, oil, suspension,emulsion, nanoparticles, liposomes, granules or functionalized surface. Thus, in this particular embodiment, the invention relates to an antibacterial composition comprising as active ingredient at least one mutated lactonase as defined above. In a particular embodiment, said composition may also contain a pharmaceutically acceptable vehicle. In a particular embodiment, said composition described above may be formulated with at least one excipient suitable for its use in the form of a solution, oil, suspension, emulsion, nanoparticles, liposomes, granules or functionalized surface. Thus, in this particular embodiment, the invention relates to a phytosanitary composition comprising as active ingredient at least one mutated lactonase as defined above. In this embodiment,the invention also relates to a composition comprising as active ingredient at least one mutated lactonase as defined above for its use in human health, in particular for the prevention and / or treatment of pathologies linked to bacterial infections. In all aspects of the present invention, the term "treatment" means the means of treating a declared pathology, the symptoms of which are visible. In all aspects of the present invention, the term "prevention" means the means of preventing said pathology from occurring. In a particular embodiment, said bacterial infections are caused by bacteria using homoserine lactone substrates to communicate. In this embodiment, the invention also relates to a composition comprising as active ingredient at least one mutated lactonase as defined above for its use in human health,in particular for the prevention and / or treatment of bacterial infections, such as pneumonia or nosocomial diseases, wounds, burns, eye infections, diabetic foot, for the prevention and / or treatment of dysbiosis, or for the prevention and / or treatment of dental plaque. In a particular embodiment, said bacteria are in particular chosen from: Acinetobacter sp., Brucella sp., Burkholderia sp., Chromobacterium sp., Enterobacter sp., Hafnia sp., Klebsiella sp., Kluyvera sp., Pandoraea sp., Proteus sp., Pseudomonas sp., Rahnella sp., Vibrio sp. and Yersinia sp. In a particular embodiment, said composition may also contain a pharmaceutically acceptable vehicle. In a particular embodiment, said composition described above can be formulated with at least one excipient suitable for its use in the form of a solution, oil, suspension, emulsion, nanoparticles,of liposomes, granules or functionalized surface. In this particular embodiment, the invention also relates to a composition comprising as active ingredient at least one mutated lactonase as defined above for its use in animal health, in particular for the prevention and / or treatment of bacterial infections, the prevention and / or treatment of dysbiosis, the prevention and / or elimination of biofilms present in breeding tanks and aquariums. In a particular embodiment, said bacterial infections are caused by bacteria using homoserine lactone substrates to communicate. In a particular embodiment, said bacteria are in particular chosen from: Aeromonas sp., Aliivibrio sp., Brucella sp., Burkholderia sp., Chromobacterium sp., Edwardsiella sp., Enterobacter sp., Halomonas sp., Pseudomonas sp., Vibrio sp. and Yersinia sp. In a particular embodiment,said composition may also contain a pharmaceutically acceptable vehicle. In a particular embodiment, said composition described above may be formulated with at least one excipient suitable for its use in the form of a solution, oil, suspension, emulsion, nanoparticles, liposomes, granules or functionalized surface. In another particular embodiment, the invention also relates to a composition comprising as active ingredient at least one mutated lactonase as defined above, said composition being applied for the prevention and / or treatment of plant infections such as fire blight, black leg, rots, cankers, wilting, necrosis, burl disease, Stewart's disease, Granville's disease, Moko's disease, yellow vine disease. In this particular embodiment,said infections are caused by bacteria using homoserine lactone substrates to communicate. In this particular embodiment, said bacteria are in particular chosen from: Acidithiobacillus sp., Agrobacterium sp., Azospirillum sp., Bradyrhizobium sp., Burkholderia sp., Dickeya sp., Erwinia sp., Gluconacetobacter sp., Mesorhizobium sp., Nitrobacter sp., Pantoea sp., Pectobacterium sp., Pseudomonas sp., Ralstonia sp., Rhizobium sp., Serratia sp. and Sinorhizobium sp. In another particular embodiment, the invention relates to the use of at least one mutated lactonase as defined above for the prevention and / or treatment of plant infections such as fire blight, black leg, rots, cankers, wilting, necrosis, burl disease, Stewart's disease, Granville's disease, Moko's disease, yellow vine disease. In this particular embodiment,said infections are caused by bacteria using homoserine lactone substrates to communicate. In this particular embodiment, said bacteria are in particular chosen from: Acidithiobacillus sp., Agrobacterium sp., Azospirillum sp., Bradyrhizobium sp., Burkholderia sp., Dickeya sp., Erwinia sp., Gluconacetobacter sp., Mesorhizobium sp., Nitrobacter sp., Pantoea sp., Pectobacterium sp., Pseudomonas sp., Ralstonia sp., Rhizobium sp., Serratia sp. and Sinorhizobium sp. In a particular embodiment, the invention relates to a composition comprising as active ingredient at least one mutated lactonase as defined above, for use on material contaminated or likely to be contaminated by bacteria using homoserine lactone substrates to communicate and form biofilms. In a particular embodiment,said material contaminated or likely to be contaminated by bacteria using homoserine lactone substrates to communicate and form biofilms is chosen from: - medical devices such as dressings, catheters, endoscopes, implants, nebulizers - medical equipment - submerged surfaces such as boat hulls, port or oil infrastructure which may be the target of biofouling or biocorrosion, - industrial installations such as cooling towers, air conditioning systems, bioreactors, pipes, nebulizers, misters, basins, - swimming pools, spas, balneotherapy devices, basins. In a particular embodiment, said biofilms contain in particular one of the following species: Aliivibrio sp., Chromobacterium sp., Dinoroseobacter sp., Halomonas sp., Pseudomonas sp.,Roseobacter sp. and Vibrio sp. In all these aspects and in a particular embodiment, said mutated lactonase of the invention is present at an effective dose, which depends on the nature of the bacteria to be eliminated. In all these aspects and in a particular embodiment, the composition as described above may additionally comprise at least one antibiotic, or at least one biocide, or at least one disinfectant agent or at least one bacteriophage. According to the invention, the term "antibiotic" means any agent capable of killing a bacterium or of reducing, limiting or inhibiting its growth. According to the present invention, the antibiotics may be bactericidal antibiotics or bacteriostatic antibiotics. The term "bactericidal antibiotics" means any agent capable of killing a bacterium. The term "bacteriostatic antibiotics" means any agent capable of reducing, limiting or inhibiting bacterial growth, without killing the bacteria. According to the invention,"Disinfectant" means any substance applied to a non-living (inert) or living object (such as skin for example) and capable of killing or inhibiting the growth of microorganisms present on the object. A disinfectant for bodily use, that is to say applied to the external surfaces of the body, such as the skin for example, is called an "antiseptic". According to the invention, "biocide" means any substance or preparation intended to destroy, repel or render harmless harmful organisms, to prevent the action of harmful organisms or to combat them, by chemical or biological action. In other words, biocides are substances exerting an action on or against harmful organisms. According to the invention, "bacteriophage" means any virus capable of infecting bacteria. Two types of bacteriophages can be distinguished: - lytic phages which infect the bacteria,hijacks its cellular machinery to reproduce and destroys the cell to release new phages - lysogenic, or temperate, phages, which insert their DNA into that of the bacteria in the form of a prophage. According to the present invention, the term "bacteriophages possibly naturally present in the environment or not" means bacteriophages naturally present in the environment as well as bacteriophages not present in the environment and added by a third party in order to eliminate bacteria. In a particular embodiment, said antibiotic may be selected from the group consisting of: Amikacin, Amoxicillin, Amoxicillin / clavulanate, Ampicillin, Amprolium, Apramycin, Aspoxicillin, Aureomycin, Avilamycin, Azithromycin, Bacitracin, Bambermycin, Baquiloprim, Benzylpenicillin, Bicozamycin, Carbadox, Cefacetrile, Cefalexin, Cefalonium, Cefalotin, Cefapyrin, Cefazolin, Cefdinir, Ceftazidime Cefquinome, Ceftiofur, Ceftriaxone,Cefuroxime, Chloramphenicol, Chlortetracycline, Ciprofloxacine, Clarithromycine, Clindamycine, Cloxacilline, Colistine, Dalbavancine, Danofloxacine, Decoquinate, Diclazuril, Dicloxacilline, Difloxacine, Doripenem, Doxycycline, Enramycine, Enrofloxacine, Ertapenem, Erythromycine, Florfenicol, Flumequine, Fosfomycine, Framycetine, acide fusidique, Gentamicine, Gentamicine Sulfate, Gramicidine, bromhydrate d'halofuginone, Hetacilline, Imipeneme, Imipenem / cilastatine, Josamycine, Kanamycine, Kitasamycine, Laidlomycine, Lasalocide , Levofloxacine, Lincomycine, chlorhydrate de lincomycine, Maduramycine, Marbofloxacine, Mecillinam, Meropeneme, Miloxacine, Minocycline, Mirosamycine, Monensine, Moxifloxacine, Nafcilline, acide nalidixique, Narasine, Neomycine, Neomycine / oxytetracycline, Neosporine, Nicarbazine, Norfloxacine, Novobiocine, Ofloxacine, Orbifloxacine, Oritavancine, Oxacilline, acide oxolinique , Oxytetracycline, Paromomycine, hydroxyde de penethamate, Penicilline,Penicilline G Potassium, Penicilline procaine, Penicilline V potassium, Phenethicilline, Phenoxymethylpenicilline, Pirlimycine, Polymyxine, Polymyxine B, Polysporine (bacitracine / polymyxine), Pristinamycine, Rifampicine, Rifaximine, Roxarsone, Salinomycine, Semduramicine, Spectinomycine, Spiramycine, Streptomycine, Sulfachlorpyridazine, Sulfadiazine, Sulfadimerazine, Sulfadimethoxazole, Sulfadimethoxine, Sulfadimethoxine et ormetoprim 5:3, Sulfadimidine, Sulfadoxine, Sulfafurazole, Sulfaguanidine, Sulfamethazine, Sulfamethoxazole / trimethoprime, Sulfamethoxine, Sulfamethoxypyridazine, Sulfamonomethoxine, Sulfanilamide, Sulfaquinoxaline, Sulfasalazine, Sulfisoxazole, Surfactine, Telavancine, Terdecamycine, Tetracycline, Thiamphenicol, Tiamuline, Ticarcilline, Tilmicosine, Tobicilline, Tobramycine, Trimethoprime, Trimethoprime / Sulfonamide, Tulathromycine, Tylosine, Valnemuline, Vancomycine, Virginiamycine. Dans un mode de réalisation particulier,said biocide may be selected from the group consisting of: active biocidal peroxides such as hydrogen peroxide, mono- and polyfunctional alcohols, aldehydes, acids, ozone, naphtha compounds and compounds containing an alkali metal, a transition metal, a Group III or Group IV metal, a sulfur, a nitrogen or a halogen atom and mixtures of two or more of these. In a particular embodiment, said biocide is selected from the group consisting of: formaldehyde, glutaraldehyde, peracetic acid, alkali metal hypochlorites, quaternary ammonium compounds, 2-amino-2-methyl-1-propanol, cetyltrimethylammonium bromide, cetylpyridinium chloride, 2,4,4-trichloro-2-hydroxy diphenyl ether, 1-(4-chlorophenyl)-3-(3,4-dichlorophenyl) urea, zinc oxide, zinc ricinoleate, pentachlorophenol, copper naphthenate, tributyltin oxide, dichlorophene, p-nitrophenol, p-chloro-m-xylenol, beta-naphthol, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine, salicylanilide, bromoacetic acid, alkyl quaternary ammonium acetate, sodium ethylmercury thiosalicylate, sodium orthophenylphenate, n-alkyl (C2 to Cs) dimethyl benzyl ammonium chloride, organoborates, 2,2-(1-methyltrimethylenedioxy)-bis-(4-methyl-1,3,2-dioxaborinane), 2,2-oxybis(4,4,6-trimethyl)-1,3,2-dioxaborinane, ethylene glycol monomethyl ether, parahydroxybenzoates, organoboron compounds, 8-hydroxyquinoline, sodium pentachlorophenate, alkyl dimethyl ethyl benzyl ammonium chloride, alkylammonium salts, 1,3,5-triethylhexahydro-1,3,5-triazine, chromate strontium, halogenated phenols, 2-bromo-4-phenylphenol, silver salts such as silver nitrate, silver chloride, silver oxide and elemental silver, organic peroxides, silver sulfadiazine, sodium dichloro-S-triazinetrione, 4-chloro-2-cyclohexylphenol, 2-chloro-4-nitrophenol, paraffin substitute,3-chloro-3-nitro-2-butanol, 2-chloro-2-nitro-1-butanol stearate, 2-chloro-2-nitrobutyl acetate, 4-chloro-4-nitro-3-hexanol, 1-chloro-1-nitro-1-propanol, 2-chloro-2-nitro-1-propanol, triethyltin chloride, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 1,3-dichloro-5,5-dimethylhydantoin, tris(hydroxymethyl)nitromethane, nitroparaffins, 2-nitro-2-ethyl-1,3-propanediol, 2-ethyl-2-nitro-1,3-propanediol, 2-methyl-2-nitro-1,3-propanediol, hexahydro-1,3,5-tris(2-hydroxyethyl)-S-triazine, hexahydro-1,3,5-tris(tetrahydro-2-furanyl)-methyl-S-triazine, methylene bis(thiocyanate), 2,2-dibromo-3- nitrilopropionamide, Beta-bromo-3-nitrostyrene, fluorinated compounds, N-ethyl-N-methyl-4-(trifluoromethyl)-2-(3,4-dimethoxyphenyl)benzamide, pentachlorophenol, dichlorophene, orthophenylphenol, di-bicyclo(3,1,1 or 2,2,1)-heptyl polyamines, di-bicyclo-(3,1,1 or 2,2,1)-heptanyl polyamines, zinc, bromine isothiazolinone. In a particular embodiment,said disinfecting agent may comprise an alcohol, a chlorine, an aldehyde, an oxidizing agent, an iodine, an ozone, a phenolic compound, a quaternary ammonium compound or a mixture of two or more thereof. In a particular embodiment, said disinfecting agent may comprise formaldehyde, orthophthalaldehyde, glutaraldehyde, silver dihydrogen citrate, polyaminopropyl biguanide, sodium bicarbonate, lactic acid, chlorine bleach, methanol, ethanol, n-propanol, 1-propanol, 2-propanol, isopropanol, hypochlorite, chlorine dioxide, dichloroisocyanurate, monochloroisocyanurate, hydantoin, sodium hypochlorite, calcium hypochlorite, sodium dichloroisocyanurate, sodium chlorite, 4-methylbenzenesulfonamide, sodium salt, 2,4-dichlorobenzyl alcohol, performic acid, paracetic acid, potassium permanganate,potassium peroxymonosulfate, phenol, phenylphenol, chloroxylenol, hexachlorophene, thymol, amylmetacresol, benzalkonuim chloride, cetyltrimethylammonium bromide, cetylpyridinium chloride, benzethonium chloride, boric acid, brilliant green, chlorhexidine gluconate, providone iodine, mercurochrome, manuka honey, octenidine dihydrochloride, polyhexamethylene biguanide, Peruvian balsam, hydrogen peroxide, organic peroxide, peroxyacid, organic hydroperoxide, peroxide salt, acid peroxides. In a particular embodiment, said bacteriophage may belong to the family of Myoviridae, Siphoviridae, Podoviridae, Corticoviridae, Cystoviridae, Inoviridae, Leviviridae, Microviridae, Plasmaviridae and Tectiviridae. In another aspect, the invention relates to a method for preventing and / or treating pathologies linked to bacterial infections,comprising administering a mutated lactonase as defined above. In another embodiment, the invention relates to a method for preventing and / or treating pathologies linked to bacterial infections, comprising administering a mutated lactonase belonging to the family of hypertermophilic phosphotriesterase-like lactonases, as defined above. Thus, in all these embodiments, said mutated lactonase may be any of the mutated lactonases described in any of the embodiments described in the first aspect of the invention. In another embodiment, said bacterial infections may be bacterial infections in plants such as fire blight, black leg, rots, cankers, wilt, necroses, burl disease, Stewart's disease, Granville's disease, Moko's disease,yellow grapevine disease. In another embodiment, said bacterial infections may be bacterial infections in animals such as dysbiosis. In another embodiment, said bacterial infections may be bacterial infections in humans such as pneumonia, nosocomial diseases, wounds, burns, eye infections, diabetic foot, dysbiosis, or dental plaque. List of Figures Figure 1 – Relative lactonase activities of the SsoPox loop 8 alanine-scanning variants using the reporter strains CV026 and Pseudomonas putida KS35. (A) and (B): Violacein production by CV026, induced by the addition of C4-HSL and C6-HSL, was measured in grayscale with ImageJ software and transformed into relative activity. High relative activity corresponds to the absence of violacein production by the reporter strain. (C),(D) and (E): The fluorescence emitted by P. putida KS35 in the presence of 3-oxo-C8-HSL, 3-oxo-C10-HSL and 3-oxo-C12-HSL was measured and transformed into relative activity. High relative activity corresponds to low fluorescence emission by the reporter strain. SsoPox V82I is the basic enzyme for mutagenesis. Figure 2 – General representation of the activities of SsoPox variants mutated at loop 8. The logarithmic values ​​of kcat / KM (s, -1 .M -1) are displayed on the circles, and are also represented by shades of gray ranging from white to black. The improvement in activity compared to SsoPox WT is represented by the size of the circles. Figure 3 – Progressive decrease in violacein produced by Chromobacterium violaceum treated with SsoPox V82I and SsoPox V82I / A275G after 16h of growth at 30°C. The dots represent bacterial growth measured by absorbance 600 nm. The bars represent extracted violacein measured by absorbance 585 nm. Figure 4 – Bioluminescence of Vibrio harveyi treated with SsoPox 5A8 (inactive), SsoPox V82I and SsoPox V82I / A275G, after 24h of growth at 30°C. Figure 5 – Growth and prodigiosin production of Serratia sp. 39006 untreated or treated with SsoPox 5A8 (inactive), SsoPox V82I and SsoPox V82I / A275G at 0.25 mg.mL -1Bacteria were cultured for 24 hours at 30°C. Black bars represent bacterial growth measured by absorbance 600 nm and gray bars represent prodigiosin production, measured by absorbance 534 nm after extraction. Figure 6 – Number of peptides related to carbapenem production identified in a 24-hour culture of Serratia sp. 39006, untreated or treated with SsoPox V82I and SsoPox V82I / A275G at 0.25 mg.mL -1. Figure 7 – A: Total number of peptides identified, by size, in the 3 culture conditions of Serratia sp. 39006. B: Variation in the number of peptides detected compared to the untreated control. Figure 8 – Principal component analyses on 506 proteins of Serratia sp. 39006. The retained proteins have at least 2 peptides counted and a normalized spectral abundance factor ≥ 0.05%. Figure 9 – The SsoPox V82I variant inhibits infection by P. atrosepticum CFBP6276 in potato. Figure 10 – Alignment of PLL sequences of extremophile archaea. A: SisLac vs SsoPox alignment. B: SacPox vs SsoPox alignment. C: Multiple alignment (SsoPox, SisLac and SacPox) with Clustal Omega. The top bar represents the variation in the consensus sequence, from black (same residue) to light gray (completely different residue). The black bar indicates loop 8. Figure 11 - Alignment of extremophile archaeal PLL sequences using Clustal Omega.The vertical bars indicate the frequency of an amino acid in all aligned sequences, from black (same residue in all sequences) to light gray (multiple different residues). The consensus sequence is defined with a threshold of 70%. The light gray horizontal bar indicates loop 8 and the black horizontal bar indicates the L242-P289 area. Examples MATERIALS AND METHODS Substrates Synthetic homoserine lactones (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL and 3-oxo-C12-HSL) were all purchased from COGER. Preparation of media and cultures Chromobacterium violaceum CV026 and C. violaceum 12742 were grown in Luria-Bertani (LB) medium. P. putida KS35 was cultured in LB medium supplemented with kanamycin at 50 µg / mL. V. harveyi DSM623 was cultured in AB medium (0.3 M NaCl, 0.05 M MgSO4, 0.2% casamino acids (Difco), supplemented with 200 µL of 1M potassium phosphate (pH 7.0), 200 µL of L-arginine 0.1 M, and 250 µL of 80% Glycerol for a final volume of 20 mL). Serratia sp. 39006 was cultured in PGM medium (5 g / L plant peptone (Sigma) and 1% Glycerol). All bacteria were grown at 30°C. Production-purification of wild-type and variant SsoPox The genes encoding the SsoPox variants were cloned into a pET22b plasmid. Productions were carried out using the Escherichia coli BL21(DE3)-pGro7 / GroEL strain. Cultures were carried out in self-inducible ZYP medium (supplemented with 100 µg.mL. -1 of ampicillin and 34 µg.mL -1 of chloramphenicol). When the absorbance at 600 nm reached a value of 0.8-1, CoCl2 was added (final concentration of 0.2 mM) as well as L-arabinose (final concentration of 2 gL -1) to induce GroEL / ES chaperone production and the temperature was lowered to 23°C for 20 hours. Cells were harvested by centrifugation (4400 g, 10 °C, 20 minutes) and resuspended in lysis buffer (50 mM HEPES pH 8, 150 mM NaCl, 0.2 mM CoCl2, 0.25 mg.mL -1 lysozyme, 0.1 mM PMSF and 10 µg. mL -1DNAseI) and were stored at -80°C. Cells were thawed and lysed by three 30-second sonication steps (Qsonica, Q700; Amplitude 45). Cell debris was removed by centrifugation (20,000 g, 10°C, 15 minutes). As SsoPox and its variants are hyperthermostable, a pre-purification step was performed by heating the lysate for 30 minutes at 70°C. Precipitated host proteins were removed by centrifugation (20,000 g, 10°C, 15 minutes). SsoPox and its variants were collected by ammonium sulfate precipitation (75%) and resuspended in 8 ml of SsoPox buffer (50 mM HEPES pH 8, 150 mM NaCl). The remaining ammonium sulfate was removed by injection onto a desalting column (HiPrep 26 / 10 desalting, GE Healthcare; ÄKTA Avant) and concentrated to 2 mL for separation by size exclusion chromatography (HiLoad 16 / 600 SuperdexTM 75 pg, GE Healthcare; ÄKTA Avant). The final purity was checked bySDS-PAGE and protein concentration was measured by the Bradford protocol(1). Mutagenesis Saturation mutagenesis directed at residues 266, 270, 271, 272, 273, 274 and 275 of the gene encoding SsoPox V82I, were performed using degenerate NNS primers and plasmid pET22b carrying the gene encoding SsoPox V82I as template. The following primers were used for mutagenesis: A266NNS forward strand: 5'- GATTGGGGCACCNNSAAACCGGAATATA -3' (SEQ ID NO: 9) A266NNS opposite strand: 5'- CTAACCCCGTGGNNSTTTGGCCTTATAT -3' (SEQ ID NO: 10) Y270NNS forward strand: 5'- CGCAAAACCGGAANNSAAACCGAAAC -3' (SEQ ID NO: 11) Y270NNS opposite strand: 5'- GTTTCGGTTTSNNTTCCGGTTTTGCG – 3' (SEQ ID NO: 12) K271NNS direct strand: 5' – CAAAACCGGAATATNNSCCGAAACTGGC – 3' (SEQ ID NO: 13) K271NNS opposite strand: 5' – GCCAGTTTCGGSNNATATTCCGGTTTTG – 3' (SEQ ID NO: 14) P272NNS forward strand: 5' – CCGGAATATAAANNSAAACTGGCACCG – 3' (SEQ ID NO: 15) P272 opposite strand: 5' –<h2 style=";text-align:left;direction:ltr">CGGTGCCAGTTTSNNTTTATATTCCGG – 3' (SEQ ID NO: 16) K273NNS direct : 5' – GGAATATAAACCGNNSCTGGCACCGCGT – 3' (SEQ ID NO: 17) K273NNS contra : 5' – ACGCGGTGCCAGSNNCGGTTTATATTCC – 3' (SEQ ID NO: 18) L274NNS direct : 5' – TATAAACCGAAANNSGCACCGCGTTG – 3' (SEQ ID NO: 19) L274NNS contra : 5'- CAACGCGGTGCSNNTTTCGGTTTATA – 3' (SEQ ID NO: 20) A275G-L274NNS direct : 5'- TATAAACCGAAANNSGGGCCGCGTTG – 3' A275G-L274NNS brin contraire: 5' TTTGGCTTTGACNNSGGCGCAACCTC -3' (SEQ ID NO: 24) The PCR amplifications are available with 2.5 U d'ADN polymerase PfuTurbo (Agilent) with fabric recommendations [95 °C, 5 min; 20x (95 °C, 30 s ; 55 °C, 1 min ; 68 °C, 15 min) ; 68°C, 25 minutes]. The ADN is digged with the DpnI enzyme to eliminate the parental methylation matrix. These cellsCompetent E. coli BL21(DE3)-pGro7 / GroEL were transformed with the plasmid mixture and plated on LB agar medium supplemented with 100 µg.mL -1 of ampicillin and 34 µg.mL -1 of chloramphenicol. From a theoretical diversity of 20 sequences per residue, 88 variants per residue were collected and cultured in a microplate containing LB (100 µg.mL -1 ampicillin and 34 µg.mL -1chloramphenicol) and 16% Glycerol. Alanine scanning (i.e., replacement of alanines by all other possible amines) of residues 263 to 279, as well as the synthesis of the double mutants A266X-A275X were performed by GenScript. The screening methods are described below. Plasmids corresponding to the most interesting variants were extracted and the genes encoding the SsoPox variants were sequenced. Library screening The plasmid library was used to transform E. coli BL21(DE3)-pGro7 / GroEL to obtain colonies possessing mutated SsoPox genes. Randomly chosen clones (88) were grown in a 96-well plate in 1 mL of ZYP medium. Chaperone production was induced after 5 h of culture at 37°C by reducing the temperature to 23°C, adding CoCl2 (0.2 mM) and arabinose (0.2%, w / v).After 20 hours of growth, enzyme lysates were obtained by partial protein purification (heating at 70°C for 30 min), followed by centrifugation (3000 rpm, 20 min). The screening assay consists of a mixture of a few microliters of enzyme lysate (from 5 to 20 µL) with different concentrations of C4-HSL, C6-HSL, 3-oxo-C6-HSL, 3-oxo-C8, 3-oxo-C10 and 3-oxo-C12 ranging from 5 µM to 1 mM in LB medium. The reporter strain CV026 or P. putida KS35 was then inoculated to the thousandth, grown overnight and the production of violacein for CV026 or fluorescence for P. putida KS35 was measured. Measurement of lactonase activity The kinetic parameters of lactonase activity were obtained using a protocol previously described in Hiblot et al. (2012)(2). The hydrolysis of lactones over time was monitored in a lactonase buffer (2.5 mM bicine pH 8.3, 150 mM NaCl, 0.2 mM CoCl2, 0.25 mM cresol violet and 0.5% DMSO) over a concentration range of 0 to 4 mM depending on the solubilities of the different lactones. Cresol violet (pKa 8.3 at 25 °C) is a pH indicator used to monitor the hydrolysis of the lactone ring by acidification of the medium. The molar extinction coefficient at 577 nm was evaluated by measuring the absorbance of the buffer over a concentration range of 0 to 0.35 mM acetic acid. For all experiments, each point was performed in triplicate and Gen5.1 software was used to evaluate the initial degradation rate at each substrate concentration. Kinetic parameters were obtained using a regression of the Michaelis-Menten equation with GraphPad Prism 7 software. Thermostability Melting temperatures (Tm) were obtained by differential scanning fluorimetry (DSF). Experiments were performed on the CFX96 Touch™ Real-Time PCR Detection System (Bio-Rad). SsoPox variants were diluted to 0.2 mg.mL.-1 in Tris buffer (50 mM Tris-HCl, pH 7) supplemented with SYPRO® orange 200X (Sigma-Aldrich). Denaturation was monitored using the FRET channel. The temperature was increased from 35 to 95°C (with an increment of 0.5°C / 15 sec). For some variants, guanidinium chloride was used at concentrations between 0.5 and 2 M. Data were fitted with the sigmoidal Boltzmann equation using GraphPad Prism 7 software, and the Tm at 0 M guanidinium chloride was extrapolated by linear regression. RESULTS 1. V82I Mutation During the first rounds of mutagenesis, a spontaneous mutation appeared at position 82, replacing the initial Valine with an Isoleucine. This mutation, although positioned far from the active site or loop 8, significantly enhanced the activities of SsoPox lactonase for 5 of the 6 substrates tested (Table 2). Protein sequence: V82I (SEQI ID NO: 25) NETTLRLIKDGYSDKIMISHDYCCTIDWGTAKPEYKPKLAPRWSITLIFEDTIPFLKRN GVNEEVIATIFKENPKKFFS Table 2 - Kinetic parameters measured for the SsoPox V82I mutant and improvement compared to SsoPox WT. These results highlight the relevance of the V82 position in SsoPox activity. The V82I mutation was then added to the W263I variant, showing an overall increase in lactonase activity on each substrate tested (Table 3). This mutation was then retained on the template gene for subsequent rounds of mutagenesis. Protein sequence: V82I / W263I (SEQI ID NO: 46) Table 3 - Kinetic parameters measured for the SsoPox V82I / W263I mutant and improvement over SsoPox W263I.

[0002] 2. Alanine-scanning All amino acids in loop 8 (except the two alanine residues: A266 and A275) were mutated by an alanine (alanine-scanning) to probe their respective impact on lactonase activity. The 15 enzymes obtained are: W263A, G264A, T265A, K267A, P268A, E269A, Y270A, K271A, P272A, K273A, L274A, P276A, R277A, W278A, S279A, and all possess the V82I mutation. The activity of the variants was screened on five acyl-homoserine lactones (C4-HSL, C6-HSL, 3-oxo-C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL) with different acyl chain lengths to characterize variations in enzymatic activities (Figure 2). 5 of 14 mutations of loop 8 residues increased the relative activity on C4-HSL compared to the reference (Figure 2-A). 12 of 14 mutations enhanced the degradation of C6-HSL (Figure 2-B). For 3-oxo-C8-HSL, mutations of 13 residues had a positive impact on degradation (Figure 2-C).10 mutations on loop 8 increased the activity on 3-oxo-C10-HSL (Figure 2-D) while 3 mutations were able to significantly increase the activity on 3-oxo-C12-HSL (Figure 2-E). These results confirm the impact of mutations on loop 8 residues of SsoPox on lactonase activity. These impacts highlight the possibility of modulating SsoPox activity by mutating loop 8 residues. Following these results, loop 8 residues A266, Y270, K271, P272, K273, L274 and A275 were exhaustively mutated by all other amino acids by site-directed saturation mutagenesis. The obtained enzyme libraries were screened on short HSL chains to identify variants with improved activity. 3. Kinetic characterization of mutants a. V82I / W263A Detected as an enhanced variant on 3-oxo-C10 and 3-oxo-C12-HSL, SsoPox V82I / W263A was purified and characterized (Table 4).This mutant had significantly increased activity on 3-oxo-C12-HSL, with a kcat / K. M 101 times higher than SsoPox WT. Protein sequence: V82I / W263A (SEQ ID NO: 26) Table 4 - Kinetic parameters measured for the SsoPox V82I / W263A mutant and improvements over SsoPox WT. b. A266NNS Enzyme Library Five variants were isolated from the A266NNS library by the CV026 screen for short-chain AHLs. The corresponding mutations were identified as follows: Protein sequences: The catalytic efficiencies (kcat / KM) of these variants were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL) (Table 5). Table 5- Kinetic parameters measured for SsoPox V82I / A266 mutants and improvements over SsoPox WT. . . . All 5 mutants, screened on short-chain HSLs, showed increased activity on C4-HSL, up to 65 times more active for SsoPox V82I / A266V on C4-HSL. SsoPox V82I / A266G has improved activity on C6-HSL and 3-oxo-C6-HSL by a factor of 2. For longer-chain HSLs, all mutants showed reduced activity compared to the wild-type enzyme (Table 5). c. Y270NNS enzyme library The Y270NNS enzyme library identified a variant of interest: V82I / Y270F. Protein sequence: (SEQ ID NO: 32) Catalytic efficiencies (kcat / K M ) of this variant were determined against six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 6 - Kinetic parameters measured for SsoPox V82I / Y270F and improvements over SsoPox WT. As observed with the A266NNS enzyme library, SsoPox V82I / Y270F has enhanced activities on C4-HSL, C6-HSL and 3-oxo-C6 HSL. However, the decrease in activity on C8-HSL and 3-oxo-C10-HSL is less drastic compared to the wild-type enzyme (Table 6). d. K271NNS enzyme library The K271NNS enzyme library led to the identification of the V82I / K271L variant. Protein sequence: (SEQ ID NO: 33) The catalytic efficiencies (kcat / KM) of this variant were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 7 - Kinetic parameters measured for SsoPox V82I / K271L and improvements over SsoPox WT. V82I / K271L 4.69 (± 0.79) x 10 20.21 The activity on short-chain HSLs of SsoPox V82I / K271L is strongly enhanced, up to 44-fold higher on C4-HSL (Table 7). e. P272NNS Enzyme Library Screening of the P272NNS enzyme library revealed the V82I / P272L mutant with enhanced activity on 3-oxo-C8-HSL. Protein sequence: V82I / P272L (SEQI ID NO: 47) f. K273NNS Enzyme Library The K273NNS enzyme library led to the identification of the V82I / K273N variant. Protein sequence: (SEQ ID NO: 34) The catalytic efficiencies (kcat / KM) of these variants were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 8 - Kinetic parameters measured for SsoPox V82I / K273N and improvements over SsoPox WT.

[0003] The K273N mutation improved activities for C6-HSL and 3-oxo-C6-HSL (Table 8). g. L274NNS Enzyme Library The L274NNS enzyme library led to the identification of the V82I / L274V variant. Protein sequence: (SEQ ID NO: 35) Catalytic efficiencies (kcat / K M ) of these variants were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 9 - Kinetic parameters measured for SsoPox V82I / L274V and improvements over SsoPox WT. ί The L274V mutation improved activities on C4-HSL, C6-HSL, and 3-oxo-C6-HSL (Table 9). h. A275NNS Enzyme Library Screening of the A275NNS library led to the identification of three variants. The corresponding mutations were identified as follows: Protein sequences: The catalytic efficiencies (kcat / KM) of these variants were determined against six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 10 - Kinetic parameters measured for SsoPox V82I / A266 mutants and improvements over SsoPox WT. Mutations of the A275 residue allowed to identify the most interesting mutants for the degradation of C4-HSL: in fact, the mutants V82I / A275G, V82I / A275M and V92I / A275W are 297, 46 and 159 times more active than SsoPox WT on this lactone. An improvement is also noted for C6-HSL and 3-oxo-C6-HSL. The activities on longer chain lactones decreased compared to the wild-type enzyme (Table 10). i. V82I / R277A Detected as an improved variant on all the lactones tested, SsoPox V82I / R277A was purified and characterized (Table 11). This mutant is 1.8 to 20.4 times more active than the wild-type enzyme on the different lactones tested. Protein sequence: V82I / R277A (SEQ ID NO: 39) Table 11 - Kinetic parameters measured for the SsoPox V82I / R277A mutant and improvements compared to SsoPox WT. j. V82I / S279A Detected as an improved variant on all tested lactones, SsoPox V82I / S279A was purified and characterized (Table 12). This mutant has an increased activity up to 19.6 times on C4-HSL. Protein sequence: V82I / S279A (SEQ ID NO: 40) Table 12 - Kinetic parameters measured for the SsoPox V82I / S279A mutant and improvements over SsoPox WT. k. A266NNS-A275NNS Enzyme Library Mutations at residues A266 and A275 led to the identification of SsoPox variants more active against short-chain AHLs. A new enzyme library was created, combining random mutations at these two residues. Screening of the library led to the identification of four mutants with improved kinetic parameters. Protein sequences: - V82I / A266G / A275F (SEQ ID NO: 41) - V82I / A266G / A275M (SEQ ID NO: 42) The catalytic efficiencies (kcat / KM) of these variants were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 13 - Kinetic parameters measured for SsoPox V82I / A266 / A275 mutants and improvements over SsoPox WT. − − These triple mutants have enhanced activities on C4-HSL, up to 130-fold for SsoPox V82I / A266G / A275M. Their C6-HSL and 3-oxo-C6 HSL activities are enhanced up to 35-fold. The V82I / A266G / A275Y variant has the highest kcat / KM ever measured on a SsoPox variant (Table 13). l. L274NNS-A275G Enzyme Library Preliminary analyses of the enzyme structure showed that the A275G mutation changes the orientation of the L274 residue, leading to new interactions with the HSL substrate. A new enzyme library was created combining the A275G mutation with random mutations on L274. A mutant of interest was discovered: V82I / L274Q / A275G. Protein sequence: (SEQ ID NO: 45) The catalytic efficiencies (kcat / KM) of this variant were determined on six HSLs (C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C10-HSL, 3-oxo-C12-HSL). Table 14 - Kinetic parameters measured for SsoPox V82I / L274Q / A275G and improvements over SsoPox WT. These combined mutations improved the enzyme's activity on C4-HSL, C6-HSL, and 3-oxo-C6-HSL (Table 14). m. Abstract The selected SsoPox variants show a strong increase in activity for short-chain HSLs, from C4-HSL to C6-HSL. The greatest improvements were obtained on C4-HSL, with several variants more than 100 times more active on this substrate. The kcat / KM on C6-HSL are also increased by a factor of 100 (Figure 3). In addition, all these variants retained a melting temperature above 85 °C, thus not affecting the hyperthermostability of the enzyme (Table 15). Therefore, it is possible to design variants combining several mutations without impacting the ability of the enzyme to withstand potentially denaturing industrial processing steps. Table 15 – Melting temperature of the SsoPox variants. These results highlight the importance of loop 8 for SsoPox activity, and the possibility of modulating its activity spectrum by mutating the residues composing this area of ​​the enzyme. 4. PHENOTYPIC IMPACT ON MODEL BACTERIA The SsoPox mutants presented above have been shown to have a greater impact than the wild-type enzyme on quorum sensing-related phenotypes in several bacteria. The impacts of the A275G mutation on quenching of various bacterial strains are described below a. Chromobacterium violaceum The quorum sensing of Chromobacterium violaceum 12472 regulates the production of violacein, a purple pigment, through the production and detection of different HSLs. SsoPox is known to inhibit this violacein production by degrading HSLs, without interfering with bacterial growth.Here, the SsoPox V82I / A275G mutant is able to inhibit violacein production at lower concentrations than SsoPox V82I, confirming its increased degradation activity on short-chain HSLs (Figure 4). b. Vibrio harveyi Quorum sensing by Vibrio harveyi induces the establishment of several phenotypes, including the production of bioluminescence. SsoPox V82I / A275G completely quenches the bioluminescence emission of V. harveyi, while the same concentration of SsoPox V82I does not reduce this phenotype compared to the inactive enzyme (Figure 5). c. Serratia sp.39006 Serratia sp. ATCC 39006 is a Gram-negative bacterium that is virulent in potato and animal models. It produces two quorum-sensing regulated antibiotics, prodigiosin and a carbapenem(3). The impact of the SsoPox V82I / A275G mutant compared to SsoPox V82I on various phenotypes of this bacterial strain is studied.SsoPox V82I / A275G is able to completely inhibit prodigiosin production in Serratia sp. 39006, while SsoPox V82I only slightly reduces this phenotype compared to the control (Figure 6). Similarly, treatment with SsoPox V82I / A275G significantly reduces the expression of carbapenem-related proteins, while treatment with SsoPox V82I shows no difference compared to the control (Figure 7). Proteomic analyses were performed on Serratia sp. 39006, grown without enzyme, with SsoPox V82I or SsoPox V82I / A275G. Treatment with SsoPox V82I / A275G caused greater changes in protein translation levels than SsoPox V82I compared to the untreated culture (Figure 8-DB), despite an equivalent amount of peptides detected (Figure 8-A). These results confirm the greater influence of SsoPox V82I / A275G on Serratia phenotypes.Principal component analysis confirmed the difference in impact of these two enzymes on Serratia sp.39006, with good separation of conditions on one dimension. (Figure 9). These results highlight that the A275G mutation, which increases the short-chain HSL degradation activity of the SsoPox V82I variant, has a greater impact on QS-related phenotypes on three different bacteria, demonstrating the importance of loop 8 residues in improving quorum quenching efficiency by SsoPox. d. Pectobacterium atrosepticum Pectobacterium atrosepticum CFBP6276 was grown overnight at 30°C. 5 mm thick Mona Lisa potato slices were prepared and pierced at three distinct locations. Each spot was filled with 20 µL of SsoPox buffer (control) or SsoPox buffer containing 0.1 mg of enzyme.After drying, each spot was inoculated with a 20 µL drop of SsoPox buffer containing 103 CFU of P. atrosepticum CFBP6276 and incubated at room temperature (23-24°C) and high humidity for 72h. No maceration was detected when inoculated potatoes were protected with the SsoPox V82I variant. 5. SEQUENCE SIMILARITIES WITH OTHER PHOSPHOTRIESTERASES-LIKE-LACTONASE (PLL) The previous results demonstrate the impact of mutations in loop 8 residues on lactonase activity and the phenotypic impact of SsoPox. SsoPox possesses high similarities in protein sequence (Figure 11) and three-dimensional structure(2, 4) with other PLLs from hyperthermophilic archaea: SisLac, isolated from Saccharolobus islandicus and SacPox from Saccharolobus acidocaldarius. The conservation of loop 8 residues among these PLLs (88% identity and 94% similarity) confirms its essential role in the lactonase activity of PLLs.All PLLs from the genus Saccharolobus share very high sequence identity with the SsoPox sequence (>75%). Loop 8 is highly conserved by each enzyme, with a minimum of 88% identity. Alignment of 49 additional amino acids adjacent to loop 8 yields a percent identity of over 90%, with the exception of the PLL from S. acidocaldarius with 79% identity (Table 16 – Figure 12). Table 16 – Percent identity of various PLLs from the genus Saccharolobus to the SsoPox sequence. Alignment and identities were obtained using blastp.

[0004]

[0005] REFERENCES 1. Bradford, M. M. (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry. 72, 248–254 2. Hiblot, J., Gotthard, G., Chabriere, E., and Elias, M. (2012) Structural and Enzymatic characterization of the lactonase SisLac from Sulfolobus islandicus. PLoS ONE. 10.1371 / journal.pone.0047028 3. Wilf, N. M., Williamson, N. R., Ramsay, J. P., Poulter, S., Bandyra, K. J., and Salmond, G. P. C. (2011) The RNA chaperone, Hfq, controls two luxR-type regulators and plays a key role in pathogenesis and production of antibiotics in Serratia sp. ATCC 39006: Role of Hfq in Serratia sp. ATCC 39006. Environmental Microbiology.13, 2649–2666 4. Bzdrenga, J., Hiblot, J., Gotthard, G., Champion, C., Elias, M., and Chabriere, E. (2014) SacPox from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius is a proficient lactonase. BMC Res Notes.7, 333

Claims

Claims 1. A mutated lactonase belonging to the hypertermophilic phosphotriesterase-like lactonase family, said mutated lactonase comprising: - a first mutation by substitution of one amino acid in a first consensus sequence SEQ ID NO: 1 of a wild-type lactonase, which first consensus sequence in said wild-type lactonase is represented by SEQ ID: 1: IRF-[M / S]-E-[K / R]-XVK-[A / T / E]-TGIN (SEQ ID: 1) X represents the amino acid V, which first consensus sequence in said mutated lactonase is represented by SEQ ID NO: 2: IRF-[M / S]-E-[K / R]-X1-VK-[A / T / E]-TGIN (SEQ ID NO: 2) X1 represents the substituted amino acid chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G, and I, in particular A or I,-at least one other mutation by substitution of one amino acid in a second consensus sequence of wild-type lactonase represented by SEQ ID: 3: Xa-G-[T / I]-Xb-[K / R]-PE-Xc-Xd-Xe-Xf-Xg-Xh-P-Xi-W-Xj (SEQ ID NO: 3), Xa is chosen from the group consisting of W, T, A, F, V, I, M and L, Xb represents amino acid A, Xc is chosen from the group consisting of Y and L, Xd represents amino acid K, Xe represents amino acid P, Xf represents amino acid K, Xg represents amino acid L, Xh represents amino acid A, Xi is chosen from the group consisting of R and K, Xj represents amino acid S, which second consensus sequence in said substitution-mutated lactonase is represented by SEQ ID: 4: X2-G-[T / I]-X3-[K / R]-PE-X4-X5-X6-X7-X8-X9-PX 10 -WX 11 (SEQ ID NO: 4) at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11being substituted, said mutated lactonase having increased lactonase activity compared to said wild-type lactonase.

2. Mutated lactonase according to claim 1, wherein, -at least one other substitution mutation involves at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11of the sequence SEQ ID: 4 in which: X2 is chosen from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A, G and I, in particular A, X3 is chosen from the group consisting of hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C, in particular G, I, M, and V, in particular G, X4 is chosen from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular F, X5 is chosen from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular L, X6 is chosen from the group consisting of hydrophobic amino acids V, I, L, M, F, G, A, W, Y, and C, in particular L, X7 is chosen from the group consisting of polar amino acids S, T, N, Q, E, D, R, and H, especially N, X8 is chosen from the group consisting of hydrophobic amino acids V, I, M, F, G, A, P, W, Y, and C, especially V, X9 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, P, W, Y, and C, in particular G, M, and W, X 10 is chosen from the group consisting of the non-bulky amino acids G, P, L, I, A, D, C, S, T, and N, in particular A, X 11 is chosen from the group consisting of the hydrophobic amino acids V, I, L, M, F, G, A, P, W, Y, and C, in particular A.

3. Lactonase mutated according to claim 1 or 2, wherein X1 represents I.

4. Lactonase mutated according to any one of claims 1 to 3, wherein at least one other substitution mutation involves at least one of the amino acids X2, X3, X4, X5, X6, X7, X8, X9, X 10 or X 11from sequence SEQ ID: 4 in which: X2 is chosen from the group consisting of A and I, X3 is chosen from the group consisting of V, I, M, G, and T, X4 represents F, X5 represents L, X6 represents L, X7 represents N, X8 represents V, X9 is chosen from the group consisting of F, M, G, Y, C, and W, X 10 represents A, X 11 represents A.

5. Mutated lactonase according to any one of claims 1 to 4, wherein at least one other substitution mutation involves amino acids X3 and X9 of the SEQ ID sequence: 4, in which: X3 is chosen from the group consisting of I, and G, X9 is chosen from the group consisting of F, M, Y and C.

6. Mutated lactonase according to any one of claims 1 to 5, wherein said mutated lactonase has a sequence identity of at least 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% with the sequences SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, and SEQ ID NO: 47 provided that said mutated lactonase retains increased lactonase activity compared to said wild-type lactonase. 7.Mutated lactonase as defined in any one of claims 1 to 6, for use in: - disrupting quorum-sensing in bacteria using homoserine lactone substrates to communicate, - limiting or inhibiting biofilm formation.

8. Composition comprising as an active ingredient at least one mutated lactonase as defined in any one of claims 1 to 7 for use in human health, in particular for the treatment of bacterial infections, such as pneumonia or nosocomial infections, wounds, burns, eye infections, diabetic foot, for the treatment of dysbiosis, or for the treatment of dental plaque, said bacterial infections preferably being caused by bacteria using homoserine lactone substrates to communicate, said bacteria being selected in particular from: Acinetobacter sp., Brucella sp., Burkholderia sp., Chromobacterium sp., Enterobacter sp., Hafnia sp., Klebsiella sp., Kluyvera sp., Pandoraea sp., Proteus sp., Pseudomonas sp., Rahnella sp., Vibrio sp. and Yersinia sp.

9. Composition comprising as an active ingredient at least one mutated lactonase as defined in any one of claims 1 to 7, for use in animal health in particular for the treatment of bacterial infections, the treatment of dysbiosis, said bacterial infections preferably being caused by bacteria using homoserine lactone substrates to communicate, said bacteria being in particular selected from: Aeromonas sp., Aliivibrio sp., Brucella sp., Burkholderia sp., Chromobacterium sp., Edwardsiella sp., Enterobacter sp., Halomonas sp., Pseudomonas sp., Vibrio sp. and Yersinia sp. 10.A plant protection composition comprising as an active ingredient at least one mutated lactonase as defined in any one of claims 1 to 7, said composition being applied for the treatment of plant infections such as fire blight, blackleg, rots, cankers, wilt, necrosis, brucellosis, Stewart's disease, Granville disease, Moko disease, and yellow vine disease, said infections preferably being caused by bacteria using homoserine lactone substrates to communicate, said bacteria being selected in particular from: Acidithiobacillus sp., Agrobacterium sp., Azospirillum sp., Bradyrhizobium sp., Burkholderia sp., Dickeya sp., Erwinia sp., Gluconacetobacter sp., Mesorhizobium sp., Nitrobacter sp., Pantoea sp., Pectobacterium sp., and Pseudomonas. sp., Ralstonia sp., Rhizobium sp., Serratia sp. and Sinorhizobium sp.. 11.Use of a composition comprising at least one mutated lactonase as defined in any one of claims 1 to 7, on material contaminated or likely to be contaminated by bacteria using homoserine lactone substrates to communicate and form biofilms, said contaminated material being selected from: - medical devices such as dressings, catheters, endoscopes, implants, nebulizers - medical equipment - submerged surfaces such as boat hulls, port or oil infrastructure that may be subject to biofouling or biocorrosion, - industrial installations such as cooling towers, air conditioning systems, bioreactors, piping, nebulizers, misting systems, basins. - swimming pools, spas, hydrotherapy equipment, basins, the said biofilms preferably containing one of the following species: Aliivibrio sp., Chromobacterium sp., Dinoroseobacter sp., Halomonas sp., Pseudomonas sp., Roseobacter sp. and Vibrio sp.

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