46 results about "Alginate lyase" patented technology

The invention provides low-temperature alginate lyase and application thereof, namely alginate lyase with low-temperature catalytic activity, which is separated from marine-derived cold monad bacteria, and the amino acid sequence of the alginate lyase is SEQ ID NO: 1; the amino acid sequence of the alginate lyase after the signal peptide is removed is SEQ ID NO: 3. The algin lyase Alg3889 provided by the invention has the optimal reaction temperature of about 10-16 DEG C, has good temperature stability, and still keeps more than 70% of enzyme activity after being incubated at 0-70 DEG C for 1 hour; the optimum pH value of the strain is 8.0, after the strain is incubated in a buffer system with the pH value of 3.0-10.6 for 12 h, about 90% of the highest enzyme activity can be kept, and the strain has high acid resistance and alkali resistance. The degradation product of the alginate oligosaccharide is alginate oligosaccharide with the polymerization degree of 2-6, and the alginate oligosaccharide has high application value.

The invention relates to algin lyase FsAly7Z with high activity and high thermal stability, which is mainly used for producing brown algae trisaccharide, and an engineering bacterium and application of the algin lyase FsAly7Z. The invention provides an alginate lyase FsAly7Z derived from marine uncultured microorganisms and a preparation method of the alginate lyase FsAly7Z. The FsAly7Z has extremely high thermal stability, and compared with the enzyme activity loss of more than 50% after most enzymes are treated at 40 DEG C for 60 min, the FsAly7Z shows remarkably excellent thermal stability under the same condition, and the half-life period of the FsAly7Z exceeds 24 h; the FsAly7Z can be used for efficiently degrading sodium alginate and a polyG section which is difficult to degrade, and meanwhile, the FsAly7Z also shows the catalytic efficiency superior to that of most similar enzymes; and the content of brown algae trisaccharide in the enzymolysis product is high, so that the subsequent separation and purification process can be simplified, and the production cost can be reduced. In a word, the FsAly7Z is extremely high in thermal stability and excellent in catalytic efficiency, has both economical efficiency and conversion efficiency, can efficiently produce alginate oligosaccharide, is used for analyzing the structure and function association of alginate lyase, and has wide market prospects in the fields of medicine, food industry and the like.

The invention provides an alginate lyase mutant Amut8C as well as a coding gene and application thereof, belongs to the technical field of gene engineering and enzyme engineering, and can solve the problem that existing alginate lyase cannot meet the requirements of severe reaction conditions such as high temperature and acidity in industrial application. The amino acid sequence of the alginate lyase mutant Amut8C disclosed by the invention is as shown in SEQ ID NO. 1. According to the space structure of the alginate lyase Algt, disulfide bonds in molecules are analyzed, the alginate lyase is mutated, and the obtained alginate lyase mutant Amut8C has heat resistance, acid and alkali resistance and digestive enzyme tolerance, and compared with the alginate lyase Algt, the alginate lyase mutant Amut8C has the advantages that the content of the alginate lyase mutant Amut8C is increased, and the content of the alginate lyase mutant Amut8C is increased. The alginate oligosaccharide with the polymerization degree of 1-4 prepared from the alginate lyase mutant Amut8C under the same enzymolysis condition is higher in yield. The method can be applied to the fields of feeds, foods, detergents or biofuels.

The invention relates to an intestinal probiotic genetically engineered bacterium as well as a construction method and application thereof, and belongs to the technical field of genetic engineering. According to the invention, Escherichia coli is used as an expression host, endogenous recessive plasmid pMUT1 gene and pMUT2 gene are knocked out, an exo-algin lyase gene and an open-loop uronic acid monomer dehydrogenase gene are subjected to heterologous expression, and a 2-keto-3-deoxy-gluconate kinase gene and a 2-keto-3-deoxy-6-phosphate-gluconate aldolase gene are subjected to overexpression. According to the invention, an endogenous recessive plasmid pMUT2 of Escherichia coli Nissle 1917 is utilized, metabolic pathways of algin and degradation products thereof are introduced, and a stable passage engineered strain EcNc-pMUT2 '-4 which can be proliferated by utilizing algin and degradation products thereof and is free of antibiotic markers is obtained, and the engineered strain has good intestinal tract probiotic performance.

The invention discloses exo-type alginate lyase VsAly7C as well as a recombinant strain and application of the exo-type alginate lyase VsAly7C. The amino acid sequence of the exo-alginate lyase is as shown in SEQ ID No.4, and the nucleotide sequence for coding the amino acid sequence is as shown in SEQ ID No.1. The suitable reaction temperature of the exo-alginate lyase is 24-28 DEG C, and the exo-alginate lyase has high stability at 0-20 DEG C, so that the exo-alginate lyase can effectively degrade a substrate at low temperature, and belongs to cold-adapted alginate lyase. The exo-type alginate lyase has the capability of degrading alginate, polyG and polyM, the degradation mode is exo-type, and a final degradation product is unsaturated alginate trisaccharide and has NaCl dependence. The invention further constructs a recombinant vector and a recombinant thallus containing the exo-alginate lyase VsAly7C coding gene, and a good foundation can be provided for industrial application and production of unsaturated alginate oligosaccharides.

The invention belongs to the technical field of seaweed functional products, and particularly relates to fucoidin as well as a preparation method and application thereof, in particular to application of the fucoidin in food and preparation of medicines for adjuvant treatment of age-related maculopathy. According to the invention, alginate lyase is adopted to carry out enzymolysis on seaweed, and the fucoidin with the molecular weight of 20-60 kDa is obtained after treatment of multi-stage alcohol precipitation, hydrogen peroxide degradation and membrane interception. Experimental results show that the fucoidin has the effect of repairing retinal cells, can effectively improve maculopathy, can be used for preparing related products for treating age-related macular degeneration, and provides safer natural material support for treatment of age-related macular degeneration.

The invention belongs to the field of biological enzyme engineering, and particularly relates to a high-stability alginate lyase mutant and a preparation method thereof. The invention relates to algin lyase mutants AncAlyA1 and AncAlyA2 with high stability. The algin lyase mutants AncAlyA1 and AncAlyA2 are characterized in that coded protein sequences of the algin lyase mutants AncAlyA1 and AncAlyA2 are shown as SEQ ID NO.2 and SEQ ID NO.3. The algin lyase is optimized through an ancestor sequence reconstruction technology, the activity of the optimized enzyme is remarkably improved, and algin degradation can be more efficiently catalyzed. And the heat stability and pH adaptability are enhanced, so that the enzyme keeps activity under wider temperature and pH conditions, the method adapts to complex environmental conditions in industrial production, and the performance reduction caused by environmental fluctuation is reduced. In addition, by optimizing the fermentation process, the enzyme yield is greatly increased, the production cost is reduced, and the economic benefit is improved. Due to the improvements, the technology is superior to the prior art in the aspects of enzyme catalysis efficiency, stability, adaptability and yield, and a better solution is provided for efficient utilization and industrial production of algin.

The invention discloses a fermentation type seaweed granular fertilizer and a fermentation method thereof, and belongs to the technical field of biological fertilizers, plant active substances of enzymolysis seaweed active powder, grain byproducts and organic nutrition of soybean meal are fused, after microbial fermentation, nutrition release is more balanced, robust growth of crops can be promoted, and the yield and quality can be improved; seaweed residues are secondarily utilized through an enzymolysis technology, macromolecular substances are degraded into micromolecular active components through alginate lyase and cellulase, enzymolysis seaweed active powder is prepared, the nutritive value of seaweed is excavated to the maximum extent, the cost of raw materials is reduced, nano zeolite serves as a carrier of microelements, iron ions are reduced and stabilized through potassium borohydride, and then iron ions are reduced and stabilized through potassium borohydride; and then the nitrohumic acid is used for chelating elements such as zinc, iron and boron, and the adsorption performance of the nano zeolite is combined, so that the double stability of the chelated trace elements and the porous carrier is realized.

The invention provides an alginate lyase mutant, a recombinant expression vector, an engineering bacterium and application of the alginate lyase mutant, belongs to the technical field of gene engineering and enzyme engineering, and can solve the technical problem that alginate lyase which has high enzyme activity and good thermal stability and can be used for efficiently preparing alginate oligosaccharide needs to be developed. The alginate lyase mutant disclosed by the invention is an alginate lyase mutant Amut6, and the amino acid sequence of the alginate lyase mutant Amut6 is as shown in SEQ ID NO. 1. The alginate lyase mutant Amut6 is prepared from alginate lyase Algt1 through an error-prone PCR reaction, compared with the alginate lyase Algt1, the enzyme activity and the thermal stability of the alginate lyase mutant Amut6 are both improved, and the preparation efficiency of alginate oligosaccharide with the polymerization degree of 1-4 is higher.

The present invention provides laundry detergent compositions comprising an alginate lyase enzyme and an anionic surfactant. The present disclosure also provides methods of treating a fabric by contacting the fabric with an aqueous wash liquor having a detergent composition therein. The compositions and methods are useful, inter alia, for improving whiteness of the fabric, for improving soil removal effect in the fabric, for malodor removal from the fabric, for anti-wrinkle benefit, anti-redeposition benefit, and / or for improving drying effect of the fabric.

The present disclosure provides compositions including alginate microspheres capable of self-degradation upon rehydration, the alginate microspheres comprising alginate, alginate lyase, and divalent metal ions. The present disclosure also provides methods of making compositions including alginate microspheres capable of self-degradation upon rehydration, comprising alginate, alginate lyase, and divalent metal ions. The present disclosure also provides methods of inducing an embolism in a subject in thereof, and syringes containing the compositions of the present disclosure for use in the methods thereof.

The application discloses a kind of alginate lyase mutants, coding gene, recombination expression vector and genetically engineered bacteria, belong to genetic engineering technical field.The application uses alginate lyase PpAly7A as starting template, and obtains the mutant with relatively specific activity and thermal stability by site-directed mutagenesis and combination mutation.The relative specific activity of mutant C169A, C66A / C169A, C66A / C169A / C214A, E87Q is increased to 131.42%, 162.89%, 160.97%, 133.82% respectively compared with wild enzyme PpAly7A.The destruction of Glu180-Arg178 salt bond (E180Q) improves thermal stability, and the half-life of the mutant at 50 DEG C is increased to 7.246d compared with wild enzyme PpAly7A, and the site can be used as a new target for subsequent rational design.

The invention provides a homogeneous immune FRET (Fluorescence Resonance Energy Transfer) analysis method and application of alginate, and belongs to the technical field of analytical chemistry and biosensing. The alginate fluorescent probe is prepared by respectively marking FRET donors and receptors on alginate by utilizing the high-specific recognition characteristic of a catalytic inactivated alginate lyase or carbohydrate binding module thereof on the alginate, and the probe is randomly combined on alginate molecules with a linear repetitive skeleton in a novel'sugar-coated haw 'structure. At an appropriate probe: alginate binding ratio, FRET donors and receptors are close to each other and generate FRET signals. The lanthanide complex is used as a fluorescence donor, and short-life background fluorescence interference in a biological sample is effectively filtered out by utilizing the long-life luminescence characteristic of the lanthanide complex. Compared with a conventional polysaccharide analysis method which usually needs a complex pretreatment process and relatively long detection time, the method disclosed by the invention can realize high-sensitivity, high-specificity, rapid and homogeneous immunofluorescence quantitative detection of algal polysaccharides in a biological sample.

The present application relates to a kind of mediated zymolytic enzyme of brown algae and application of double transcription unit recombinant bacteria of oxyprotein and brown algae, belong to genetic engineering technical field, the recombinant engineering bacteria is composed of two transcription units, one transcription unit is GAP-alpha-Vgb-AOX1TT, another transcription unit is AOX-alpha-102C300C-AOX1TT, two transcription units are expressed in tandem in pPICZ alphaA plasmid.The present application also provides the preparation method and application of the recombinant bacteria.The recombinant bacteria of the present application can improve the secretion expression efficiency of brown algae zymolytic enzyme, especially can be expressed in low-oxygen environment.

A C-terminal truncated alginate lyase and its application. This invention belongs to the fields of bioengineering, genetic engineering, and enzyme engineering, and relates to a C-terminal truncated alginate lyase TY2 designed with molecular docking assistance, its encoding gene, recombinant vector, strain, and its application in the preparation of low-polymerization degree alginate oligosaccharides. Using wild-type MhAly6 as the parent, the truncation boundary was determined through structural prediction and molecular docking. A portion of the linker peptide was retained, and the C-terminal GH28 family domain was deleted to obtain the truncated form TY2. TY2 has approximately twice the specific activity of the wild-type enzyme, and even higher residual activity after incubation at 45°C for 1 hour, achieving a synergistic improvement in catalytic activity and thermal stability. + The relative enzyme activity reached 4.3 times that of the control group, which can degrade pretreated Sargassum powder. The product is mainly ΔDP2–ΔDP4 low-polymerization brown algae oligosaccharides, which are suitable for related enzymatic degradation and oligosaccharide preparation.

The application discloses a alginate lyase mutant E87Q, a coding gene, a recombinant expression vector and a genetically engineered bacterium, and belongs to the technical field of genetic engineering. The application takes alginate lyase PpAly7A as a starting template, and a mutant with improved relative specific activity is obtained through site-directed mutagenesis. Compared with the wild enzyme PpAly7A, the mutant E87Q has a relative specific activity increased to 133.82%, and the corresponding site can be used as a new target for subsequent rational design.

The invention relates to a composition for treating thyroid nodules and a preparation method thereof, and belongs to the technical field of biological medicine, the composition comprises trepang body wall fibrinolytic small peptides, kelp small molecule active components, a selfheal-saussurea lappa composite extract and a safflower-ligusticum wallichii composite extract; the sea cucumber body wall fibrinolytic small peptide is a product obtained by performing common enzymolysis on sea cucumber body wall powder through alkaline pectinase, bromelain and trypsin and then performing common enzymolysis through subtilisin and lumbrukinase. The kelp micromolecular active component is a product obtained by performing enzymolysis extraction on kelp powder through alginate lyase, performing purification through an X-5 macroporous adsorption resin column and performing ultrafiltration. The selfheal-saussurea lappa composite extract is a product obtained by extracting selfheal powder and saussurea lappa powder with an ethanol water solution, purifying with a polyamide resin column and performing ultrafiltration; the safflower-Szechuan lovage rhizome composite extract is a product obtained by extracting safflower powder and Szechuan lovage rhizome powder with an ethanol aqueous solution, purifying with an NKA-9 macroporous resin column and performing ultrafiltration.

The invention discloses an alginate lyase mutant, a coding gene, a recombinant expression vector and a genetically engineered bacterium, and belongs to the technical field of genetic engineering. According to the invention, alginate lyase PpAly7A is taken as a starting template, and a mutant with improved relative specific activity and thermal stability is obtained through site-specific mutagenesis and combined mutagenesis. Compared with a wild enzyme PpAly7A, the relative activity of the mutants C169A, C66A / C169A, C66A / C169A / C214A and E87Q is respectively improved to 131.42%, 162.89%, 160.97% and 133.82%, and the relative activity of the mutants C66A / C169A, C66A / C169A / C214A and E87Q is respectively improved to 131.42%, 162.89%, 160.97% and The thermal stability is improved by damage (E180Q) of a Glu180-Arg178 salt bond, the half-life period of the mutant at 50 DEG C is prolonged to 7.246 d compared with that of a wild enzyme PpAly7A, and the site can be used as a new target for subsequent rational design.

The invention discloses a mucus type pseudomonas aeruginosa bacteriophage separation method based on recombinant alginate lyase, according to the separation method, mucus type pseudomonas aeruginosa bacteriophage is obtained based on recombinant alginate lyase separation, and the amino acid sequence of the recombinant alginate lyase is shown as SEQ ID NO.2. An alginate lyase gene algL in genomic DNA of a pseudomonas aeruginosa standard strain PAO1 is used as a target gene, a recombinant plasmid is constructed, induced expression is completed in escherichia coli, and the recombinant alginate lyase with high purity and high alginate degradation activity is obtained. Based on the recombinant alginate lyase, the bacteriophage which shows a high splitting effect on the mucus type pseudomonas aeruginosa is screened, the problem that the mucus type pseudomonas aeruginosa bacteriophage is difficult to separate is solved, and a technical basis is provided for development of drugs for treating infectious diseases caused by the mucus type pseudomonas aeruginosa.

The invention discloses an alginate lyase VxAly7B-CM mutant obtained through directed evolution of a T7 biosensor as well as a directed evolution method and application of the alginate lyase VxAly7B-CM mutant. The nucleotide sequence of a mutant 1 of the alginate lyase VxAly7B-CM provided by the invention is as shown in SEQ ID No.3, the amino acid sequence of the mutant 1 is as shown in SEQ ID No.4, the nucleotide sequence of a mutant 2 is as shown in SEQ ID No.5, and the amino acid sequence of the mutant 2 is as shown in SEQ ID No.6. The high specific activity and high stability of the mutant provided by the invention exceed those of most reported alginate lyase. The algin lyase VxAly7B-CM mutants 1 and 2 keep a catalytic mode and degradation products consistent with those of a wild type VxAly7B-CM, the degradation mode is an incision type, and the degradation final products are mainly unsaturated disaccharide, trisaccharide, tetrasaccharide and pentasaccharide. The invention also constructs a recombinant vector and a recombinant strain containing the mutant, and the recombinant vector and the recombinant strain can be used for degrading seaweed or algin to prepare AOS in industrial production.

The invention relates to the technical field of seaweed active component extraction, and discloses a gradient enzymolysis-ultrasonic coupling double-seaweed active component extraction process, which solves the problems proposed in the background technology, and comprises the following steps: 1, brown algae pretreatment and first-stage enzymolysis; the preparation method comprises the following steps: crushing a brown algae raw material until the particle size is 50-100 meshes, and adding a buffer solution with the pH value of 5.0-6.0 according to a material-liquid ratio of 1: 15-1: 20; adding cellulase, carrying out enzymolysis at 45-50 DEG C for 30-60 minutes, and synchronously applying 28kHz / 300W pulse ultrasound; adjusting the pH value of the system to 7.0-7.5, adding alginate lyase, and continuing enzymolysis at 50-55 DEG C for 40-80 minutes; 2, green algae pretreatment and second-stage enzymolysis; the preparation method comprises the following steps: crushing a green alga raw material until the particle size is 80-120 meshes, and adding a buffer solution with the pH value of 6.5-7.0 according to a material-liquid ratio of 1: 10-1: 15; adding xylanase and sulfatase, carrying out enzymolysis for 60-90 minutes at 55-60 DEG C, and synchronously applying 35kHz / 500W continuous ultrasonic waves. The method has the effects of increasing the extraction rate, reducing the energy consumption and being high in activity retention rate.

This invention provides a method for extracting astaxanthin from Haematococcus pluvialis and its application. The method includes the following steps: S1. Raw material pretreatment; S2. Enzymatic hydrolysis with a complex enzyme; S3. Solubilization with a surfactant; S4. Adsorption by iron(III) oxide-cellulose porous microspheres; S5. Magnetic separation and washing; S6. Astaxanthin elution and microsphere recovery; S7. Concentration and drying. This invention utilizes a complex enzyme consisting of cellulase, alginate lyase, and mannanase to synergistically hydrolyze the multilayer polysaccharide structure of thick-walled spores of Haematococcus pluvialis, thereby fully releasing astaxanthin. Furthermore, iron(III) oxide-cellulose porous microspheres with benzyl and octyl surface modifications are used for highly selective adsorption of astaxanthin, combined with magnetic separation technology, thus improving the astaxanthin yield. The extraction process of this invention is carried out under medium-low temperature conditions, and butylated hydroxytoluene is added to the eluent, effectively avoiding thermal degradation, photolysis, and oxidation of astaxanthin, resulting in a high retention rate of antioxidant activity in the obtained astaxanthin.

The application discloses a method for improving salt adaptability of PL7 family alginate lyase. First, surface amino acid, enzyme catalytic site and conservative site are analyzed, then mutation sites are selected according to the analysis, so that positively charged amino acids in the target wild type PL7 family alginate lyase are mutated into negatively charged amino acids or non-charged amino acids; then mutation schemes of each mutation site are selected according to the analysis; if the conservative site analysis result shows that the mutation site exists negatively charged amino acid on other PL7 family alginate lyases, the mutation site is preferentially mutated into glutamic acid or aspartic acid with negative charge; if the site does not exist negatively charged amino acid on other PL7 family alginate lyases, the mutation site is mutated into negatively charged amino acid, and the mutation is preferentially performed into more appearing amino acid. Finally, the salt adaptability is regulated, and the alginate lyase suitable for low salt catalytic environment is obtained.

A truncated alginate lyase with wide temperature adaptability and its applications. This invention belongs to the fields of marine microbial genetic engineering and enzyme engineering, specifically disclosing a truncated alginate lyase, Aly7YΔCBM16ΔCBM32, and its applications. The amino acid sequence of this truncated form is shown in SEQ ID NO.4, and the nucleotide sequence is shown in SEQ ID NO.3. Compared with the wild type, this truncated form exhibits approximately 2-fold increased specific enzyme activity, more than 3-fold extended half-life at 40°C, and a significantly wider temperature and pH adaptability range. Furthermore, after normalization to 100% of the maximum activity of each enzyme, this truncated form retains approximately 78% activity in 1% SDS, demonstrates enhanced catalytic activity for Poly G, and achieves approximately 90% relative enzyme activity even under sodium-free conditions. This truncated form exhibits excellent environmental tolerance and can be used for the efficient preparation of low-polymerization alginate oligosaccharides primarily composed of ΔDP2–ΔDP4.

The application discloses an endolytic alginate lyase AlgC2m and application thereof. The biological enzyme is derived from a Paenibacillus-like bacterium enriched in a seaside soil sample. The application also discloses a recombinant expression vector and a recombinant host containing the alginate lyase AlgC2m gene. The application clones a new alginate lyase gene AlgC2m, which is 1320 bp in size, encodes 439 amino acids, and is classified into the PL-7 family. The similarity of the alginate lyase to alginate lyases in the same family is only 38%. The alginate lyase AlgC2m provided by the application has the function of degrading sodium alginate to prepare alginate oligosaccharide, and the main degradation product is unsaturated alginate disaccharide and trisaccharide, and has certain industrial application value.

The invention relates to the technical field of microorganisms, in particular to a vibrio strain capable of efficiently degrading algin and application of the vibrio strain. The invention relates to a vibrio strain capable of efficiently degrading algin, which is preserved in China General Microbiological Culture Collection Center (CGMCC), the name is (Vibrio sp.) MBPDH9, the preservation number is CGMCC No.35925, the preservation date is September 15, 2025, and the address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The vibrio strain provided by the invention can be used for producing the alginate lyase, the product of the alginate lyase for degrading alginate is only brown algae disaccharide, the product specificity is high, and the vibrio strain is beneficial to being applied to industrial production. Meanwhile, the fermentation culture condition of the vibrio strain is further subjected to single-factor experimental research, and precondition research is provided for subsequent large-scale industrial production of the vibrio strain. The vibrio strain provided by the invention can efficiently degrade sargassum horneri in a seawater environment, is a dominant strain for resource utilization of brown algae, and has the advantage of environmental protection.

The invention provides a flight control fertilizer composition for promoting wheat growth and increasing yield as well as a preparation method and application thereof, and relates to the technical field of agricultural fertilizers. The invention relates to a flight control fertilizer composition. The seaweed preservative is prepared from the following raw materials: 240 to 320 parts of an amino acid mixture, 40 to 65 parts of an enzymolysis seaweed extract, 6 to 15 parts of sodium dodecyl benzene sulfonate, 6 to 15 parts of sodium alkyl naphthalene sulfonate, 6 to 15 parts of sodium dodecyl sulfate, 110 to 160 parts of anhydrous dipotassium phosphate, 160 to 200 parts of potassium pyrophosphate, 20 to 40 parts of ethylene glycol and 6 to 15 parts of zinc sodium ethylene diamine tetraacetate. The amino acid mixture comprises the following components: aspartic acid, glutamic acid and arginine; the preparation method comprises the following steps: carrying out freeze thawing pretreatment on brown algae, and carrying out enzymolysis treatment by using cellulase, alginate lyase and mannase, so as to obtain the enzymolysis seaweed extract. All the components interact with one another, so that the synergistic effects of promoting wheat growth and germination and increasing the yield are achieved.

The invention belongs to the technical field of biology, and discloses incision type alginate lyase RiAlyPL6, an expression strain of the incision type alginate lyase RiAlyPL6 and a preparation method of unsaturated alginate oligosaccharide. The endo-algin lyase RiAlyPL6 provided by the invention comprises an amino acid fragment with a sequence as shown in SEQ ID NO: 1 or a variant fragment with at least 75% of homology with the fragment as shown in SEQ ID NO: 1. The endo-type alginate lyase RiAlyPL6 has substrate preference to poly-G, can realize high-specificity degradation of poly-G in an endo-degradation mode, and is of great significance to preparation of alginate oligosaccharide with biological activity.

The present invention relates to a co-oxygen protein VHb, its recombinant bacterium X33-pPICZαA-102C300C-Vgb and applications, belonging to the technical field of genetic engineering. The nucleotide sequence of the gene of the co-oxygen protein VHb is as shown in SEQ ID N0.1, and the gene of the co-oxygen protein VHb can be used to improve the efficiency of the secretion of alginate lyase by the Pichia pastoris engineering bacterium. The present invention also provides that the amino acid sequence of the co-oxygen protein VHb is as shown in SEQ ID N0.2. The present invention also provides a recombinant expression vector and a recombinant bacterium X33-pPICZαA-102C300C-Vgb comprising an alginate lyase gene and the gene of the co-oxygen protein VHb. The recombinant bacterium improves the utilization rate of oxygen by the bacterial cells in a low-oxygen environment in the later stage of fermentation, and finally improves the yield of alginate lyase.

The invention provides an alginate lyase mutant, a plasmid, a recombinant strain and application thereof, belongs to the technical field of gene engineering and enzyme engineering, and can solve the technical problem that the enzyme activity of the existing alginate lyase cannot meet the efficient, controllable and industrial preparation of alginate oligosaccharide. The alginate lyase mutant disclosed by the invention is an alginate lyase mutant AMDW2, and the amino acid sequence of the alginate lyase mutant AMDW2 is as shown in SEQ ID NO. 1. The alginate lyase mutant AMDW2 is obtained by mutating D amino acid selected around an active center GQIH sequence into W amino acid by original alginate lyase Algt1, and compared with the original alginate lyase Algt1 which is not mutated, the alginate lyase mutant AMDW2 has higher enzyme activity and thermal stability; the alginate oligosaccharide with low polymerization degree can be prepared by using the minimum substrate pentasaccharide, and can be applied to the fields of feeds, foods, cleaning agents or biofuels.