An antimicrobial composition

Abstract

The present invention relates to an antimicrobial composition that not only cleans hard and soft inanimate surfaces but also delivers antimicrobial efficacy against both gram positive and gram negative bacteria. This is achieved through a combination of a rhamnolipid surfactant, an amino acid surfactant and select chelating agent.

Description

[0001] AN ANTIMICROBIAL COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to an antimicrobial composition. It more particularly relates to a composition that not only cleans hard and soft inanimate surfaces but also delivers antimicrobial efficacy against both gram positive and gram negative bacteria. The composition is especially useful in cleaning and disinfection of hard surfaces like those in the kitchen e.g. utensils but also may be used to disinfect fabric.

[0004] Background of the Invention

[0005] Disinfecting and cleaning compositions are of great benefit to individuals, since proper use generally reduces the number of germs and pathogens the individual is exposed to. Such compositions are used for cleaning and disinfecting hard surfaces e.g. those in the kitchen like utensils and in other areas like toilets, bathrooms, and floors at homes and public places. Clothes and fabrics like bedsheets also require disinfection especially when used by babies in addition to clothes and fabrics used in hospitals. Disinfecting action can be achieved by including conventional bleaches like hypochlorite in such compositions but many consumers do not like the smell of chlorine that is generated during the use of such compositions. Compositions comprising cationic surfactants also provide efficient disinfection but they may have to be used at high concentrations. Further, it is a really difficult problem to formulate cleaning and disinfection compositions with minimal amount of conventional antibacterial agents which are effective in killing both gram positive as well as gram negative bacteria. It is an even more difficult problem to solve if this result can be achieved without use of any conventional antibacterial agents but only through select combination of conventionally used surfactant and other cleaning agents.

[0006] It is thus an object of the present invention to provide for a composition that can disinfect surfaces to ensure desired kill of both gram negative as well as gram positive bacteria.

[0007] Summary of the Invention

[0008] The first aspect of the present invention relates to an antimicrobial composition comprising

[0009] (i) 0.01 to 2.5 wt% a rhamnolipid;

[0010] (ii) 0.025 to 2.5 wt% of an amino acid surfactant; and

[0011] (iii) 0.005 to 2% wt of a chelating agent selected from one or more of methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid sodium (GLDA), sodium gluconate, and capryl hydroxamic acid. Another aspect of the present invention relates to a method of killing both gram positive and gram negative bacteria from a surface comprising the step of contacting the surface with a composition of the first aspect preferably diluted with water.

[0012] Detailed Description of the Invention

[0013] For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of” or "composed of'. Thus, the term "comprising" is meant not to be limiting to any subsequently stated elements, but rather to optionally also encompass nonspecified elements of major or minor functional importance. In other words, the listed steps or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word "about". Unless specified otherwise, numerical ranges expressed in the format "x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”.

[0014] The composition of the invention comprises two primary surfactants viz. a rhamnolipid surfactant and an amino acid surfactant. Both of these surfactants are of the anionic class.

[0015] The composition of the invention comprises a rhamnolipid. Rhamnolipids are a class of glycolipid. They are constructed of rhamnose combined with beta-hydroxy fatty acids. Rhamnose is a sugar. Fatty acids are ubiquitous in animals and plants.

[0016] Rhamnolipids are discussed in Applied Microbiology and Biotechnology (2010) 86:1323- 1336 by E. Deziel et al. Rhamnolipids are produced by Glycosurf, AGAE Technologies and Urumqi Unite Bio-Technology Co., Ltd. Rhamnolipids may be produced by strains of the bacteria Pseudomonas Aeruginosa. Rhamnolipids may also be produced by a recombinant cell of Pseudomonas Putida where the recombinant cell comprises increased activity of at least one of the enzymes a / P hydrolase, rhamnosyltransferase I or rhamnosyl-transferase II compared to the wild-type of the cell.

[0017] There are two major groups of rhamnolipids; mono-rhamnolipids and di-rhamnolipids. Monorhamnolipids have a single rhamnose sugar ring. A typical mono-rhamnolipid produced by P. aeruginosa is L-rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (RhaC C ). It may be referred to as Rha-Cw-Cw, with a formula of C26H48O9. Monorhamnolipids have a single rhamnose sugar ring.

[0018] The IIIPAC Name is 3-[3-[(2R,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2- yl]oxydecanoyloxy]decanoic acid.

[0019] Di-rhamnolipids have two rhamnose sugar rings. A typical di-rhamnolipid is L-rhamnosyl-L- rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (Rha2CioC ). It may be referred to as Rha- Rha-C- -C-10, with a formula of C32H58O13.

[0020] The IIIPAC name is 3-[3-[4,5-dihydroxy-6-methyl-3-(3,4, 5-tri hydroxy-6-methyloxan-2- yl)oxyoxan-2-yl]oxydecanoyloxy]decanoic acid.

[0021] In practice, a variety of other minor components with different alkyl chain length combinations, depending upon carbon source and bacterial strain, exist in combination with the above more common rhamnolipids. The ratio of mono-rhamnolipid and di-rhamnolipid may be controlled by the production method. Some bacteria only produce monorhamnolipid, see US5767090: Example 1 , some enzymes can convert mono-rhamnolipid to di-rhamnolipid.

[0022] In various publications mono-rhamnolipids have the notation Rha-, which may be abbreviated as Rh or RL2. Similarly, di-rhamnolipids have the notation Rha-Rha or Rh-Rh or RL1. For historical reasons "rhamnolipid 2" is a mono-rhamnolipid and "rhamnolipid 1 "is a di-rhamnolipid. This leads to some ambiguity in the usage or "RL1 " and "RL2" in the literature.

[0023] Throughout this patent specification, we use the terms mono- and di-rhamnolipid in order to avoid this possible confusion. However, if abbreviations are used R1 is mono-rhamnolipid and R2 is di- rhamnolipid. For more information on the confusion of terminology in the prior art, see the introduction to US 4814272. The following rhamnolipids have been detected as produced by the following bacteria: (C12:1 , C14:1 indicates fatty acyl chains with double bonds).

[0024] Rhamnolipids produced by P. aeruginosa (mono-rhamnolipids):

[0025] Rha-C8-C10, Rha-C10-C8, Rha-C10-C10, Rha-C10-C12, Rha-C10-C12:1, Rha-C12-C10, Rha- C12:1-C10

[0026] Rhamnolipids produced by P. aeruginosa (di-rhamnolipids):

[0027] Rha-Rha-C8-C10, Rha-Rha-C8-C12:1 , Rha-Rha-C10-C8, Rha-Rha-C10-C10, Rha-Rha-C10- C12:1 , Rha-Rha-C-10-C-12, Rha-Rha-C-12-C-10, Rha-Rha-C-12:1-C-12, Rha-Rha-C10-C14:1

[0028] Rhamnolipids produced by P. aeruginosa (unidentified as either mono- or di-rhamnolipids): C8- C8, C8-C10, C10-C8, C8-C12:1 , C12:1-C8, C10-C10, C12-C10, C12:1-C10 C12-C12, C12:1- C12, C14-C10, C14:1-C10, C14-C14.

[0029] Rhamnolipids produced by P. chlororaphis (mono-rhamnolipids only):

[0030] Rha-C10-C8, Rha-C10-C10, Rha-C12-C10, Rha-C12:1-C10, Rha-C12-C12, Rha-C12:1- C12, Rha-C14-C10. Rha-C-14:1-C-10.

[0031] Rhamnolipids produced by Burkholdera pseudomallei (di-rhamnolipids only): Rha-Rha-C14-C14.

[0032] Rhamnolipids produced by Burkholdera (Pseudomonas) plantarii (di-rhamnolipids only): Rha-Rha-C14-C14.

[0033] There are over 100 strains of P. aeruginosa on file at the American Type Culture Collection (ATCC). There are also a number of strains that are only available to manufacturers of commercial Rhamnolipids. Additionally, there are probably thousands of strains isolated by various research institutions around the world. Some work has gone into typing them into groups. Each strain has different characteristics including how much rhamnolipid is produced, which types of rhamnolipids are produced, what it metabolizes, and conditions in which it grows. Only a small percentage of the strains have been extensively studied.

[0034] Through evaluation and selection, strains of P. aeruginosa can be isolated to produce rhamnolipids at higher concentrations and more efficiently. Strains can also be selected to produce less byproduct and to metabolize different feedstock or pollutants. This production is greatly affected by the environment in which the bacterium is grown.

[0035] A typical di-rhamnolipid is L-rhamnosyl-L-rhamnosyl-p-hydroxydecanoyl-p-hydroxydecanoate (Rha2CioC with a formula of C32H58O13).

[0036] In practice a variety of other minor components with different alkyl chain length combinations, depending upon carbon source and bacterial strain, exist in combination with the above more common rhamnolipids. The ratio of mono-rhamnolipid and di-rhamnolipid may be controlled by the production method. Some bacteria only produce monorhamnolipid, see US6767090: Example 1 , some enzymes can convert mono-rhamnolipid to di-rhamnolipid.

[0037] Preferably the rhamnolipid is selected from:

[0038] Rhamnolipids produced by P. aeruginosa (mono-rhamnolipids):

[0039] Rha-C8-C10, Rha-C10-C8, Rha-C10-C10, Rha-C10-C12, Rha-C10-C12:1 , Rha-C12-C10, Rha- C12:1-C10

[0040] Rhamnolipids produced by P. chlororaphis (mono-rhamnolipids only):

[0041] Rha-C10-C8, Rha-C10-C10, Rha-C12-C10, Rha-C12:1-C10, Rha-C12-C12, Rha-C12:1- C12, Rha-C14-C10, Rha-C14:1-C10.

[0042] Mono-rhamnolipids may also be produced from P.putida by introduction of genes rhIA and rhIB from Psuedomonas aeruginosa [Cha et al. in Bioresour Technol. 2008. 99(7):2192-9]

[0043] Rhamnolipids produced by P. aeruginosa (di-rhamnolipids):

[0044] Rha-Rha-C8-C10, Rha-Rha-C8-C12:1 , Rha-Rha-C10-C8, Rha-Rha-C10-C10, Rha-RhaC10- C12:1 , Rha-Rha-C10-C12, Rha-Rha-C12-C10, Rha-Rha-C12:1-C12, Rha-Rha-C10- C14:1

[0045] Rhamnolipids produced by Burkholdera pseudomallei (di-rhamnolipids only):

[0046] Rha-Rha-C14-C14.

[0047] Rhamnolipids produced by Burkholdera (Pseudomonas) plantarii (di-rhamnolipids only):

[0048] Rha-Rha-C14-C14.

[0049] Rhamnolipids produced by P. aeruginosa which are initially unidentified as either mono- or di-rhamnolipids: C8-C8, C8-C10, C10-C8, C8-C12:1 , C12:1-C8, C10-C10, C12-C10, C12:1-C10, C12-C12, C12:1-C12, C14-C10, C14:1-C10, C14-C14.

[0050] Preferably the Rhamnolipid is L-rhamnosyl-(3-hydroxydecanoyl-p-hydroxydecanoate (RhaC Cio with a formula of C26H48O9).

[0051] Preferably, the rhamnolipid comprises at least 50 wt.% di-rhamnolipid, more preferably at least 60 wt.% di-rhamnolipid, even more preferably 70 wt.% di-rhamnolipid, most preferably at least 80 wt.% di-rhamnolipid.

[0052] Preferably the rhamnolipid is a di-rhamnolipid of formula: Rha2C8-i2Cs-i2. The preferred alkyl chain length is from Cs to C12. The alkyl chain may be saturated or unsaturated. The most preferred di-rhamnolipid is an example of a di-rhamnolipid of formula: Rha2C8-i2Cs-i2, known as Rhamnolipid R2 herein, and can be supplied from Evonik. The composition comprises rhamnolipid in 0.01 to 2.5%, preferably 0.1 to 2%, more preferably 0.25 to 1.5% by weight of the composition.

[0053] Amino acid surfactants are included in the composition of the invention. They are surfactants that may be produced by biotechnological and chemical methods using amino acids and (vegetable) oils or fat. Because amino acids and vegetable oils or fats are renewable sources, the class of amino acid surfactants are a suitable material in detergent compositions that are made from renewable sources. The combination of a polar amino acid and non-polar oil or fat chain provides molecules with high surface activity. Due to the wide variety of amino acids (and peptide) structures and the variety in the chain length of the oily or fat group, the properties of amino acid surfactant also vary, allowing for specific amino acid surfactants for specific purposes.

[0054] In the present invention, the amino acid surfactant is preferably selected from one or more of glutamates, sarcosinates, glycinates and alaninates preferably one or both of glutamate and sarcosinate. The fatty chain is preferably a C6 - C16 fatty acid chain, more preferably C10 to C16, the most preferred fatty acid chains are lauroyl and cocoyl chains. The amino acid is preferably selected from disodium lauroyl glutamate, disodium cocoyl glutamate and sodium lauroyl sarcosinate.

[0055] Since the oily or fatty chain is typically derived from natural sources, the fatty acids and alcohols they are made of are not always a pure single chain length ingredient. By Cx-Cy is generally meant that at least 50% of the alkyl chains comprise of between x and y carbon atoms, preferably at least 60%, more preferably at least 70%, still more preferably at least 80%, even more preferably at least 90%, yet more preferably at least 95%, or even at least 98%, or ideally at least 99% of the alkyl chains comprise of between x and y carbon atoms.

[0056] The amino acid surfactant is present in the composition in a concentration of 0.025 to 2.5% based on the total weight of the composition. Preferably the amino acid surfactant is present in a concentration of at least 0.05 wt%, more preferably at least 0.1 wt%, still more preferably at least 0.25 wt%, but preferably not more than 2.0 wt%, more preferably not more than 1.5 wt% based on the total weight of the composition.

[0057] The composition of the invention comprises a chelating agent selected from one or more of methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid sodium (GLDA), sodium gluconate, and capryl hydroxamic acid (CHA). GLDA herein refers to the sodium salt of L- glutamic acid N, N-diacetic acid. The preferred chelating agent is one or more of MGDA, CHA and sodium gluconate. The composition comprises 0.005 to 2.0%, preferably 0.01 to 1.5%, and more preferably 0.05 to 1.5% chelating agent by weight of the composition.

[0058] Without wishing to be bound by theory, the inventors believe that the combination of rhamnolipid, the amino acid surfactant and the chelating agent works by affecting the permeabilization of the actives across the cell membrane of the micro-organism followed by affecting the metabolism of the cell.

[0059] The composition of the invention preferably comprises a secondary surfactant which helps in thorough cleaning of the surface. By a secondary surfactant is meant a surfactant which is included in the composition of the invention which is other than the primary surfactants i.e. rhamnolipid surfactant and the amino acid surfactant. The secondary surfactant may be of the anionic, non-ionic, amphoteric or zwitterionic class. To be clear, the secondary surfactant of the anionic class is referred herein as secondary anionic surfactant.

[0060] Dishwash composition

[0061] The composition of the invention may be useful for upkeep of kitchen items e.g. utensils and dishes which may be cleaned using a dishwash composition, preferably in liquid form. The various ingredients other than the essential ingredients claimed in the present invention are summarized below. Dishwash compositions as per the invention generally comprise a total amount of 1 to 30%, preferably from 2 to 15% by weight of one or more secondary surfactants. A preferred secondary surfactant for inclusion in the composition of the invention is an anionic surfactant. Preferred secondary anionic surfactants are of the organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term “alkyl” being used to include the alkyl portion of higher acyl radicals. Examples of such materials include alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alpha-olefin sulfonates and mixtures thereof. The alkyl radicals preferably contain from 10 to 18 carbon atoms and may be unsaturated. The alkyl ether sulfates may contain from one to ten ethylene oxide or propylene oxide units per molecule, and preferably contain one to three ethylene oxide units per molecule. The counterion for anionic surfactants is generally an alkali metal such as sodium or potassium; or an ammoniacal counterion such as monoethanolamine, (MEA) diethanolamine (DEA) or triethanolamine (TEA). Mixtures of such counterions may also be employed. Sodium and potassium are preferred.

[0062] Most preferred secondary anionic surfactants are of the alkyl sulfate surfactant (PAS) class such as non-ethoxylated primary and secondary alkyl sulphates with an alkyl chain length of from 10 to 18. Some alkylbenzene sulfonates type, particularly linear alkylbenzene sulfonates (LAS) with an alkyl chain length of from 10 to 18 carbon atoms may also be included.

[0063] Preferably, dishwash compositions as per the invention may further comprise an amphoteric surfactant. Preferably, the amphoteric surfactants is selected from alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulfobetaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, having alkyl radicals containing from about 8 to about 22 carbon atoms, the term “alkyl” being used to include the alkyl portion of higher acyl radicals. More preferably, the amphoteric surfactant is selected from alkyl amidopropyl betaines, even more preferably cocoamidopropyl betaine. Amphoteric surfactant, when included, may be present in an amount ranging preferably from 0.1 to 5 wt%, more preferably from 0.1 to 4 wt%, even more preferably from 1 to 3 wt%. Mixtures of any of the above described materials may also be used. A good combination of secondary surfactants for use in the present invention in the form of a dishwash composition is one having 1 to 25 wt% anionic surfactant and 0.1 to 5 wt% an amphoteric surfactant.

[0064] Preferably, dishwash compositions may also comprise a non-ionic surfactant preferably in 0.1 to 3% based on the total weight of composition. A preferred class of such nonionic surfactant for use in the invention includes aliphatic Cs to Cis, more preferably C12 to C15 primary linear alcohol ethoxylates with an average of from 3 to 20, more preferably from 5 to 10 moles of ethylene oxide per mole of alcohol. Preferred non-ionic surfactants are the C16 / 18 alcohol ethoxylates.

[0065] Liquid dishwash composition may preferably comprise an organic acid or its salts. Preferably, the organic acid or its salt is selected from one or more of citric acid, succinic acid, malic acid, lactic acid, tartaric acid, hexanoic acid, cyclohexanoic acid, heptanoic acid, octanoic acid, 4-methyl octanoic acid, nonanoic acid, decanoic acid, benzoic acid, 4-methoxy benzoic acid and mixtures thereof. Examples of salts of organic acid include corresponding salts of these organic acids that are formed preferably with sodium and potassium, more preferably with sodium, e.g. trisodium citrate. More preferably, organic acid or its salt may further comprise maleic acid or its salt. Even more preferably, the organic acid or its salt is selected from citric acid or its salt e.g. trisodium citrate. Preferably, the composition does not comprise silver dihydrogen citrate. When the composition comprises an organic acid or its salts it is preferably included in from 0.2 to 5 wt%, preferably from 0.3 to 4 wt%, more preferably from 0.4 to 3 wt%, even more preferably from 0.5 to 3 wt%, further more preferably from 1 to 2 wt%. When the organic acid chosen is citric acid, this could be in addition to citric acid if chosen as the chelating agent, as per this invention.

[0066] When the dishwash is in liquid form, it preferably comprises water in an amount ranging from 5 to 99 wt%, more preferably from 10 to 90 wt%, even more preferably from 15 to 80 wt%, further more preferably from 20 to 70 wt%, still more preferably from 30 to 65 wt%, yet more preferably from 35 to 60 wt%, yet further more preferably from 40 to 55 wt%.

[0067] Preferably, the liquid dishwash composition further comprises one or more sequestrants. Preferably, sequestrant may be present in an amount from 0.1 to 5 wt%, more preferably from 0.25 to 4 wt%, even more preferably from 0.5 to 2.5 wt%.

[0068] A preferred sequestrant is a phosphonic acid or a salt thereof. The phosphonic acid (or salt thereof) sequestrant is preferably selected from the group consisting of 1 -Hydroxyethylidene-1 ,1 -diphosphonic acid (HEDP; commercially available as Dequest(R) 2010), Diethylenetriaminepenta(methylenephosphonic acid) (DTPMP; commercially available as Dequest(R) 2066), Hexa methylene diamine tetra(methylenephosphonic acid) (HDTMP), Amino tris(methylenephosphonic acid) (ATMP), Ethylene diamine tetra(methylenephosphonic acid) (EDTMP), Tetra methylene diamine tetra(methylenephosphonic acid) (TDTMP); and Phosphono butane tricarboxylic acid (PBTC). The most preferred sequestrant is 1 -Hydroxyethylidene-1 ,1 - diphosphonic acid (HEDP). It is preferable that the sequestrant is added to the formulation in acid form.

[0069] Optionally, liquid dishwash composition further comprises an enzyme with or without a suitable enzyme stabilizer. Preferably the composition further comprises an effective amount of at least one enzyme with or without a suitable enzyme stabilizer. Examples of suitable enzymes include pectate lyase, protease, amylase, cellulase, lipase, mannanase; with or without an appropriate stabilizing agent.

[0070] When in liquid form, the viscosity of the dishwash composition may suitably range from about 200 to about 10,000 mPa.s at 25°C at a shear rate of 21 sec1. This shear rate is the shear rate that is usually exerted on the liquid when poured from a bottle. Pourable liquid home care compositions generally have a viscosity of from 200 to 1 ,500 mPa.s, preferably from 100 to 800 mPa.s.

[0071] The liquid dishwash composition preferably has pH in the range from 2.5 to 12, more preferably from 3 to 8, and most preferably from 4 to 6.5.

[0072] The liquid dishwash composition may further comprise one or more polymers. Preferably, polymers can be cationic, anionic, amphoteric or nonionic types with molecular weights higher than 100,000 Dalton. They are known to increase the viscosity and stability of liquid compositions, to enhance in-use and after-use skin sensory feels, and to enhance lather creaminess and lather stability. Examples of polymers include polyvinyl alcohol, polyacrylic acid, silane, siloxane and mixtures thereof. If present, polymers may be present in the composition in an amount ranging preferably from 0.001 to 10 wt%, more preferably from 0.1 to 6 wt%, still further more preferably from 1 to 3 wt%.

[0073] Preferably, the composition may be used as is, i.e. neat, or it may be diluted before use. The extent of dilution is generally dependent on market choice. In some markets a more concentrated product is desired while in others a more dilute product is preferred. When the composition is a liquid dishwash compositions it is typically diluted with water in a weight ratio in the range of 1 :1 to 1 :20 more preferably from 1 :1 to to 1 :10.

[0074] The liquid dishwash composition may optionally comprise ingredients, such as fragrance, colorant, foam boosting agents, and odor absorbing materials. Laundry detergent composition:

[0075] The composition may be delivered as a laundry detergent composition which in addition to the essential ingredients of the present invention may also include 1 to 80 wt%, preferably 2 to 60 wt%, further more preferably 4 to 30 wt% secondary surfactant. The secondary surfactant is preferably an anionic surfactant, a non-ionic surfactant or mixtures thereof. Secondary anionic surfactants which may be included are listed hereinabove in the dishwash composition section. Non-ionic surfactants which may be included are also listed hereinabove in the dishwash composition section. The laundry detergent composition may be delivered in the form of a solid or as a liquid.

[0076] The laundry detergent composition in which the present invention may be delivered is preferably in the liquid form. The term liquid may encompass emulsions, suspensions, and compositions having flowable yet stiffer consistency, known as gels or pastes. Pourable liquid detergent compositions preferably have a viscosity of from 200 to 1 ,500 mPa.s, preferably from 200 to 700 mPa.s. Such compositions generally have an aqueous continuous phase. Preferably, the composition comprises at least 50% wt. water and more preferably at least 70% wt. water. Water is generally present in an amount of 20% to 99.9% preferably from 40% to 80% by weight of the composition.

[0077] Liquid laundry detergent compositions also generally comprise agents like soil release polymers, hydrotropes, co-surfactants, builders, polymeric thickeners, and shading dyes in addition to the above described ingredients. Soil release polymers (SRP) help to improve the detachment of soils from fabric by modifying the fabric surface during washing.

[0078] The SRP structure may also include capping groups to control molecular weight or to alter polymer properties such as surface activity. Preferred SRPs for use in the invention include copolyesters formed by condensation of terephthalic acid ester and diol, preferably 1 ,2 propanediol, and further comprising an end cap formed from repeat units of alkylene oxide capped with an alkyl group. The SRP, when included, may range from 0.1 to 10%, desirably from 0.3 to 7%, more preferably from 0.5 to 5% by weight of the composition.

[0079] A composition of the invention may incorporate non-aqueous carriers such as hydrotropes, cosolvents and phase stabilizers. The liquid laundry detergent composition may also optionally contain relatively low levels of organic detergent builder or sequestrant material. Examples include the alkali metal citrates, succinates, malonates, carboxymethyl succinates, carboxylates, polycarboxylates aminocarboxylates and polyacetyl carboxylates. If utilized, the organic builder materials may comprise from about 0.5 percent to 20 wt percent, preferably from 1 wt percent to 10 wt percent, of the composition.

[0080] When the composition is a liquid laundry detergent composition, it may be diluted with water in weight ratios in the range of 1 :50 to 1 :800, more preferably in the range of 1 :100 to 1 :500 to form the wash liquor.

[0081] The solid laundry compositions herein can take a variety of physical solid forms including forms such as powder, granule, ribbon, noodle, paste, tablet, flake, pastille and bar, and preferably the composition is in the form of powder, granule or a bar.

[0082] The composition according to the present invention may be made via a variety of conventional methods known in the art including dry-mixing, compaction such as agglomerating, extrusion, tableting, or spray-drying of the various compounds comprised in the detergent component, or combinations of these techniques. The powder or granule compositions preferably have a density of more than 350 grams / litre, more preferably more than 450 grams / litre or even more than 570 grams / litre.

[0083] Typical solid laundry detergent compositions comprise one or more of secondary surfactants chosen from anionic, nonionic, zwitterionic, or amphoteric types, preferably it is of the anionic type. These compositions in solid form typically comprise from 1 to 30% by weight secondary anionic surfactants. Details on the various ingredients like the anionic and non-ionic surfactants, the SRPs, hydroptopes, builders etc which are described for the liquid detergent composition may also be included in the solid detergent composition. Additionally, they may also comprise other adjuvents to provide benefits to the fabric being washed e.g. antiredeposition polymers which together may be included in 0 to 5% by weight of the composition. Builders are generally included especially to counteract the ill effects of hardness of water being used to wash the fabric and these account for up to 50% typically 10 to 30% by weight of the composition. Other fabric benefit agents like shading dyes and optical brightener may be included in up to 1 % by weight of the composition. Bleaches may sometimes be included and when it is included it accounts for up to 10% by weight of the composition and fillers generally account for up to 40% by weight of the composition.

[0084] The solid laundry detergent composition according to the present invention preferably has a pH from 7.0 to 10.5, preferably 7.0 to 10.2, still preferably from 8.5 to 10.2, when measured at 1 wt.% dilution in de-ionised water at 25°C. The composition may preferably include a buffer.

[0085] In general, it is preferred that the composition of the invention used for most applications described above is in liquid form.

[0086] The invention also relates to killing both gram positive and gram negative bacteria from a surface comprising the step of contacting the surface with a composition of the invention preferably diluted with water. The surface is preferably inanimate. The method is preferably non- therapeutic.

[0087] The invention will now be illustrated with the help of the following non-limiting examples.

[0088] Examples A-D,1 : Effect of the composition on the log kill of S. aureus.

[0089] Combination of actives as shown in Table -1 below were used to measure the log kill of

[0090] S. aureus at two time points (5 minutes and 10 minutes).

[0091] The procedure used was as follows:

[0092] The suspension test in this example is according to the common test protocol of EN1276.

[0093] Bacterial count of 108bacteria per ml was used as the bacterial culture. In this test 8ml of formulation was used together with 1 ml of bacterial culture and 1 ml of BSA solution. The BSA solution was at a concentration of 0.03% to mimic a “clean” surface condition. After the above solutions were mixed, the bacterial count was diluted 10 times, thus resulting in a bacterial count at the start of the experiment of 107bacteria per ml.

[0094] The formulation and bacteria were kept in contact for appropriate time points (5 min and 10 min, as specified in the examples below) and then neutralized (to quench the efficacy of the actives and stop its action against bacteria). With respect to a water control, the bacterial log reduction through formulations was calculated. The examples are carried out at room temperature of 23 °C.

[0095] Target organism: Staphylococcus aureus ATCC 6538 (a gram-positive bacteria). The rhamnolipid used was V10075 sourced from Evonik, Germany.

[0096] The data is summarized in Table -1 below: Table - 1

[0097] The data in table -1 above indicates that composition as per the invention (Example -1) provides for vastly enhanced improvement in log kill as compared to the individual ingredients or subset combinations.

[0098] Examples E-H.2,3: Effect of the composition on the log kill of P. aeuroc / inosa

[0099] Combination of actives as shown in Table -2 below were used to measure the log kill of

[0100] P. aeuroginosa (at 5 minutes and 10 minutes). P. aeuroginosa is a gram negative bacteria. The procedure used was the same as used in earlier in Table - 1 The data is summarized in Table -2 below:

[0101] Table - 2 The data in table -2 above indicates that compositions as per the invention (Examples 2 and 3) deliver vastly improved log kill against P. aeruginosa similar to the efficacy against S. aureus. Examples l-K, P 4,5: Effect of other chelating agents

[0102] Combination of actives as shown in Table -3 below were used to measure the log kill of S. aureus (at 5 minutes and 10 minutes).

[0103] The procedure used was the same as used in earlier in Table - 1

[0104] The data is summarized in Table -3 below:

[0105] Table - 3

[0106] The data in table -3 above indicates that compositions as per the invention (Examples 4 and 5) deliver synergistic improvement in log kill against S. aureus with other chelating agents too. Use of sodium citrate (Example P) as a chelating agent in such a composition delivers poor antimicrobial kill.

[0107] Examples M,N, 6: Effect of vet another chelating agent

[0108] Combination of actives as shown in Table -4 below were used to measure the log kill of S. aureus at very short time frame (30 seconds) and at very low concentration.

[0109] The procedure used was the same as used in earlier in Table - 1

[0110] The data is summarized in Table -4 below: Table - 4

[0111] The data in table -4 above indicates that composition as per the invention (Examples 6) delivers vast improvement in log kill against S. aureus with another chelating agents at very short time frames and at very low concentration.

[0112] It is to be understood that the experiments described above were conducted in an invitro assay to evaluate the antimicrobial behaviour. The assay was conducted at conditions simulating the cleaning action where the composition of the invention is diluted with water to a concentration which is representative of that used by the consumer when in actual use. The dilution with water as per this invention may be in a weight ratio in the range of 1:1 to 1:800, preferably in the range of 1:10 to 1:500, most preferably in the range of 1:10 to 1:250.

Claims

Claims1. An antimicrobial composition comprising(i) 0.01 to 2.5 wt% a rhamnolipid;(ii) 0.025 to 2.5 wt% of an amino acid surfactant; and(iii) 0.005 to 2 wt% of a chelating agent selected from one or more of methyl glycine diacetate (MGDA), L-glutamic acid N, N-diacetic acid sodium (GLDA), sodium gluconate, and capryl hydroxamic acid (CHA).

2. A composition as claimed in claim 1 wherein amino acid surfactant is selected from one or more of glutamates, sarcosinates, glycinates, and alaninates.

3. A composition as claimed in claim 2 wherein the amino acid surfactant is one or both of glutamate and sarcosinate.

4. A composition as claimed in any one of the preceding claims wherein the chelating agent is one or more of MGDA, CHA, and sodium gluconate.

5. A composition as claimed in any one of the preceding claims which is a dishwash composition comprising 1 to 25 wt% secondary anionic surfactant.

6. A composition as claimed in claim 5 comprising 0.1 to 5 wt% an amphoteric surfactant.

7. A composition as claimed in any one of the preceding claims 1 to 4 which is a laundry detergent composition comprising 1 to 80 wt% secondary surfactant preferably an anionic surfactant.

8. A composition as claimed in any one of the preceding claims in liquid form.

9. A method of killing both gram positive and gram negative bacteria from a surface comprising the step of contacting the surface with a composition as claimed in any one of the preceding claims preferably diluted with water.

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