395 results about "Heterologous expression" patented technology

The invention relates to an L-valine production strain as well as a construction method and application thereof, the strain is obtained by transformation through a metabolic synthesis path of L-valine, and the construction method comprises the following steps: by taking Cornebacterium glutamicum ATCC 13032 (C.glutamicum) as an original strain, carrying out editing transformation such as gene knockout, gene overexpression, gene heterologous expression, gene double-copy expression and the like on a genome of the original strain by utilizing a metabolic engineering means. The L-valine production strain disclosed by the invention can be used for synthesizing L-valine from the beginning by taking glucose as a carbon source, has the advantages of high production rate, short fermentation period, high strain stability and low cost, and lays a foundation for realizing large-scale production of L-valine. According to the fermentation tank fermentation method, the L-valine is produced in a mechanical stirring type fermentation tank by using the L-valine production strain Va1-09, 86.4 g / L of L-valine is produced by fermenting for 36 hours, and the method has a good industrial prospect.

The invention discloses a pichia pastoris engineering bacterium for synthesizing bakuchiol from de novo by converting methanol as well as construction and application of the pichia pastoris engineering bacterium. A heterologous p-coumaric acid synthesis pathway is introduced to neutral sites of different chromosomes of pichia pastoris, a high-yield p-coumaric acid strain is obtained through gene knockout, overexpression or heterologous expression of tyrosine and phenylalanine synthesis pathway key genes of a shikimic acid pathway, a heterologous bakuchiol biosynthesis pathway is introduced on the basis, and a high-yield p-coumaric acid strain is obtained. After overexpression of bakuchiol synthetase, endogenous overexpression or heterologous expression of MVA pathway key genes and exogenous acetyl coenzyme A supply pathway genes, methanol concentration optimization and bacterial strain His4 gene supplementation, the yield of bakuchiol is effectively increased to 91.2 mg / L and is increased by 59.8 times compared with that of an initial bacterial strain, and the yield of bakuchiol in a 15L fermentation tank reaches 692.8 mg / L. The method has the characteristics of high conversion efficiency, low production cost, convenience in preparation, wide industrial application prospect and the like.

The invention relates to pichia pastoris engineering bacteria and a preparation method thereof, and a method for producing cellooligosaccharide / disaccharide by using corn straws or wheat straws, and belongs to the technical field of genetic engineering. A cellulose incision enzyme gene and a cellulose excision enzyme gene are transferred into pichia pastoris engineering bacteria. The preparation method comprises the following steps: respectively inserting a cellulose incision enzyme gene and a cellulose excision enzyme gene into plasmids to construct expression vectors; transferring the expression vector into a competent cell of pichia pastoris GS115; and screening and identifying to obtain successfully transformed pichia pastoris engineering bacteria. According to the present invention, the pichia pastoris heterologous expression cellulose incision enzyme and cellulose excision enzyme are adopted to construct the pichia pastoris engineering strain capable of degrading the plant straw into the cellooligosaccharide / disaccharide, such that the reliable chassis strain is provided for the production of the starch from the cellulose;

The invention discloses a Pseudomonas putida high-yield rhamnolipid fermentation medium based on a step-by-step optimization strategy, an optimization method and application thereof, through the step-by-step strategy of component screening-single-factor optimization-multi-factor interactive optimization, a mixed carbon source and a mixed nitrogen source are taken as cores, and a Plackett-Burman test, a steepest climbing test and Box-Behnken response surface design are combined, so that the high-yield rhamnolipid fermentation medium for the pseudomonas putida high-yield rhamnolipid is obtained. Optimizing to obtain a special fermentation culture medium; two genetic engineering strains estA-2 and estA-3 are constructed by heterologous expression of key genes, and the supply and extracellular transport efficiency of a rhamnolipid synthesis precursor is enhanced; the recombinant strain is applied to the optimized culture medium, and efficient production of a shake flask and a 5L fermentation tank is achieved. The rhamnolipid yield of the estA-3 strain in a 5L fermentation tank reaches 35.59 + / -2.18 g / L, the conversion rate is 0.282 g / g, the productivity is 0.404 g / L / h, the rhamnolipid yield, the conversion rate and the productivity are obviously superior to those in the prior art, and a key technical support is provided for industrial production of rhamnolipid.

The application discloses a kind of fungal laccase mutant Lcc5-G and its expression strain and application.The application is based on the fungal laccase from Coprinopsis cinerea heterologous expression since, by site-directed mutagenesis, obtain mutant gene.After fungal induction expression containing mutant plasmid, obtain laccase mutant enzyme Lcc5-G with improved specific activity, stability and AFB1 removal efficiency.When ABTS is used as substrate, the specific activity of the mutant is improved by 3 times, and the stability of the mutant enzyme is improved to 5 times of the original enzyme at 45 DEG C and pH 7.The mutant has potential application value in oxidizing aflatoxin.

The invention belongs to the technical field of gene engineering, and discloses recombinant yarrowia lipolytica as well as a construction method and application thereof. The recombinant yarrowia lipolytica PGA1 is obtained by carrying out heterologous expression on an arabidopsis thaliana inositol oxygenase gene and a pseudomonas syringae uronic acid dehydrogenase gene in the yarrowia lipolytica by utilizing a genetic engineering technical means. The recombinant yarrowia lipolytica PGA10 capable of efficiently synthesizing glucaric acid (GA) is finally obtained by further modifying six genes of related metabolic pathways of the recombinant yarrowia lipolytica PGA1. The GA yield of the PGA10 reaches 2233.24 mg / L and is 66.27 times that of PGA1, and the effect is remarkable. The invention not only constructs a GA synthesis method, but also defines the influence of related genes such as opi1 on GA synthesis, and provides reference for the research of heterologous synthesis of GA by microorganisms.

The invention discloses a marine-derived carboxylesterase and an application of the marine-derived carboxylesterase in degradation of PET (Polyethylene Terephthalate) plastics. The amino acid sequence of the enzyme is as shown in SEQ ID NO.1, experiments show that Tm of RbCE1 is 79.5 DEG C, 40 mM of depolymerization monomers can be generated after the enzyme treats low-crystallinity PET powder at 60 DEG C for 4 hours, the catalytic activity is equivalent to that of LCC, and good degradation activity is shown. Through escherichia coli heterologous expression, 0.4 g / L high expression quantity can be achieved in a shake flask, and the potential of remarkably reducing the enzyme production cost is achieved. Therefore, the novel carboxylesterase RbCE1 is suitable for degrading PET plastics and composite materials thereof, and is a potential enzyme preparation for efficient biological catalysis of a waste PET plastic waste enzymatic depolymerization recovery treatment process.

The invention discloses a progesterone 5beta-reductase mutant and application thereof in synthesis of 5beta-dihydrosteroid, relates to the technical field of biology, and in particular relates to application of gene mining and engineering modification of progesterone 5beta-reductase derived from bacteria in asymmetric synthesis of 5beta-dihydrosteroid. According to the progesterone 5 beta-reductase LpP5beta R disclosed by the invention, the progesterone 5 beta-reductase LpP5beta R from bacteria psoromais is obtained by a gene mining method, and the progesterone 5 beta-reductase LpP5beta R can be subjected to soluble expression in escherichia coli. The mutant obtained by mutating the wild type LpP5beta R has obviously improved catalytic ability on progesterone, and can efficiently catalyze delta 4-3-carbonyl steroids such as hydrocortisone, dinorcitol and the like to generate corresponding 5beta-dihydrosteroids. According to the invention, the technical bottlenecks of poor heterologous expression and low catalytic efficiency of plant-derived progesterone 5beta-reductase are solved, and a potential biocatalyst is provided for green manufacturing of 5beta-dihydrosteroid drugs.

The invention discloses application of a scutellaria baicalensis SbMYB8 gene in promotion of anthocyanin synthesis, the application comprises the steps that the SbMYB8 gene is constructed to a plant expression vector and introduced into plant cells to promote synthesis of plant anthocyanin, and the nucleotide sequence of the SbMYB8 gene is shown as SEQ ID NO: 1, or the amino acid sequence coded by the SbMYB8 gene is shown as SEQ ID NO: 2. The MYB transcription factor SbMYB8 gene with the function of promoting anthocyanin synthesis is cloned and identified from the scutellaria baicalensis for the first time, and the blank of a transcription regulation mechanism for regulating anthocyanin metabolism in the scutellaria baicalensis is filled; the SbMYB8 gene can significantly promote accumulation of anthocyanin in various plants, shows good heterologous expression stability and adaptability, and has wide cross-species application potential.

The application provides a recombinant Aspergillus niger with high trans-aconitic acid yield and a construction method and application thereof, and relates to the technical field of genetic engineering. Specifically, the recombinant Aspergillus niger heterogeneously expresses aconitate isomerase TbrA and / or Adi1. The application provides a new engineering strain for efficient production of trans-aconitic acid, solves the source predicament of needing plant extraction or needing chemical synthesis in traditional production of trans-aconitic acid, and greatly improves the yield of trans-aconitic acid.

The invention provides a resveratrol production strain and a construction method and application thereof, according to the strain, tyrAfbr, tyrB, aroE, pntAB, ompF, aroGfbr and accA genes are up-regulated, a carbon storage regulation factor csrA gene is knocked out, the transcriptional level of a fabF gene is down-regulated through a BBaJ23113 promoter, a TAL gene from Rhodotorula glutinis, a 4CL gene from Arabidopsis thaliana and an STS gene from Vitis vinifera are heterologously expressed on a genome, and the strain carries a high-copy plasmid PET-28a-WAL at the same time; the strain takes glucose as a carbon source, resveratrol is efficiently and stably synthesized from the beginning by adopting a fermentation method, the production cost is low, and efficient production of resveratrol is realized.

The invention relates to an alcohol oxidase mutant and application thereof. Specifically disclosed are a mutant derived from Gloeophyllum trabeum alcohol oxidase (GtrAOX-M2), a nucleic acid encoding the alcohol oxidase mutant, a recombinant expression vector containing the nucleic acid, a recombinant expression transformant containing the recombinant expression vector, a preparation method of a recombinant alcohol oxidase catalyst, and a preparation method of the recombinant alcohol oxidase catalyst. The invention also discloses a method for catalyzing methanol to be oxidized into formaldehyde by using the alcohol oxidase, the alcohol oxidase mutant or the recombinant alcohol oxidase catalyst. The activity of the alcohol oxidase mutant provided by the invention is obviously improved compared with that of a female parent, and the enzyme is high in activity and can be heterologously expressed in escherichia coli, so that the alcohol oxidase mutant can efficiently oxidize methanol into formaldehyde and oxidize the methanol into formaldehyde by a one-carbon unit biological utilization methanol enzyme method; wide application prospects are shown in the aspect of subsequent conversion and generation of polyhydric alcohols.

The invention provides a strain for producing L-isoleucine as well as a construction method and application thereof. The strain is obtained by modifying a chassis strain escherichia coli XX12 by utilizing a metabolic engineering modification method, ldhA, adhE and pflB genes are deleted, the transcriptional levels of aspC, pykF, pntAB, ppK, ppc, ilvAfbr, ilvIHfbr and ygaZH genes are up-regulated, the transcriptional level of a leuA gene is down-regulated, a bcd gene derived from B.subtilis 168 and ppnK and cysK genes derived from Cornebacterium glutamicum ATCC 13032 are heterologously expressed, and the strain has the advantages that the strain can be used for producing L-isoleucine; the method has the advantages of no need of adding resistant substances, good L-isoleucine synthesis capability, short fermentation period by using glucose as a carbon source, and good economic benefit and industrial application value.

The invention discloses an escherichia coli engineering bacterium for producing 5-ALA by an anaerobic fermentation method as well as a construction method and a fermentation method of the escherichia coli engineering bacterium. The engineering bacterium is constructed by taking escherichia coli (E. coli) ZX11 as a host and performing heterologous expression on 5-ALA synthetase (HemA) from rhodobacter capsulatus. In order to improve the soluble expression level of the HemA, the HemA is subjected to fusion expression with a maltose binding protein (MBP) tag. Furthermore, the engineering bacterium can also heterologously express a visual purple protein (PR) fused with the MBP tag. The construction method of the engineering bacteria comprises the following steps: sequentially cloning the MBP-HemA fusion gene and the PR gene to an expression vector and transferring into host bacteria. By utilizing the engineering bacteria provided by the invention, anaerobic fermentation can be carried out in a culture medium taking glucose as a carbon source, and 5-ALA can be efficiently synthesized. The invention provides an effective way for realizing green and energy-saving anaerobic biological manufacturing of 5-ALA.

The invention discloses a BvM14-TAG2 gene and application thereof, and relates to the technical field of biological genes. The CDS sequence of the BvM14-TAG2 gene disclosed by the invention is as shown in SEQ ID NO. 1. The amino acid sequence of the protein coded by the BvM14-TAG2 gene is as shown in SEQ ID No. 2. According to the invention, the BvM14-TAG2 gene is utilized to construct an arabidopsis thaliana plant for heterologous expression of the BvM14-TAG2 gene, stress treatment is carried out, and the seed germination rate and root length of the plant for heterologous expression of the BvM14-TAG2 gene are both superior to those of a wild type; the biomass of a plant for heterologous expression of the BvM14-TAG2 gene is higher than that of a wild plant; the result shows that the BvM14-TAG2 gene can promote the growth and development of the plant under the salt stress, and can improve the adaptive capacity of the BvM14-TAG2 transgenic plant under the salt stress.

The invention discloses a pennisetum purpureum CpERF37 transcription factor and cold-resistant application thereof, and relates to the technical field of plant genetic engineering. According to the invention, the Pennisetum purpureum-sourced ERF transcription factor CpERF37 is cloned and functionally identified for the first time, and heterologous expression verification in a model plant arabidopsis thaliana proves that the Pennisetum purpureum-sourced ERF transcription factor CpERF37 has a remarkable effect on improving the low-temperature tolerance of plants, and functional gene resources related to low-temperature stress response are enriched. The method not only has theoretical innovation, but also has a definite application prospect, and can provide effective gene resources and technical support for cold-resistant improvement of pasture and crops.

The invention discloses a salt stress resistant gene BvAGER1 and application thereof, and relates to the technical field of biological genes, in particular to the salt stress resistant gene BvAGER1 and the application field thereof. According to the salt stress resistant gene BvAGER1 disclosed by the invention, a CDS (Coding Sequence) sequence of the gene BvAGER1 is as shown in SEQ ID NO. 1. The amino acid sequence of the protein coded by the salt stress resistant gene BvAGER1 is as shown in SEQ ID No. 2. The invention also discloses an application of the salt stress resistant gene BvAGER1 in improving the salt tolerance of plants. The BvAGER1 gene in a BvAGER1 gene heterologous overexpression plant prepared by utilizing the BvAGER1 gene can be stably inherited, the heterologous expression BvAGER1 gene can relieve the inhibition effect of salt stress on plant germination, and the inhibition effect on growth of roots and leaves of the BvAGER1 gene heterologous overexpression plant can be obviously weakened under the salt stress; the adaptive capacity under the salt stress is improved.

The invention provides application of Ustilaginoidea virens secretory protein UvWMT and a coding gene thereof in prevention and control of plant diseases. The gene sequence of the Ustilaginoidea virens secretory protein UvWMT is researched, found and cloned for the first time, and the new application of the Ustilaginoidea virens secretory protein UvWMT in disease-resistant breeding of crops such as rice is developed. Research finds that the protein is a key pathogenic factor in the process that rice is infected by ustilaginoidea virens, heterologous expression experiments further find that heterologous expression of UvWMT in rice can significantly improve the resistance of crops to various pathogenic bacteria such as ustilaginoidea virens, magnaporthe oryzae and xanthomonas oryzae, and has no significant difference in key agronomic traits compared with a wild type. An important theoretical basis is provided for rice disease-resistant breeding, crops can be safely and effectively endowed with broad-spectrum disease resistance by heterologous expression of the gene, and the gene has great application prospects and economic values in the aspects of crop breeding disease resistance improvement, rice disease prevention and control and crop yield increase and pesticide reduction.

Heterologous synthesis of a nitrogen-fixing system in a non-diazotrophic organism is a long-sought-after goal because of the significance of nitrogenase for areas related to agronomy, energy and environment. Two simplified nitrogenase analogs from Azotobacter vinelandii in Escherichia coli were successfully heterologously synthesized. One analog comprise the reductase component (NifH) and, in place of the catalytic component (NifDK), a cofactor maturase (NifEN); whereas the other analog comprised only NifEN. Metal, EPR and activity analyses verified the cluster composition and functional competence of the heterologously expressed NifH and NifEN. Moreover, NMR, nanoSIMS and growth experiments illustrated the abilities of both systems to mimic the nitrogenase in reducing N2 and incorporating the reduced N into the cellular mass. These results firmly established NifEN / NifH or NifEN as a simplified nitrogenase analog that could be engineered or expanded to facilitate future transgenic expression of nitrogenase and development of nitrogenase-based biotechnological applications.

The invention provides application of a transcription factor LcNF-YB3 of lycoris chinensis in regulating and controlling the flowering time of plants, and belongs to the technical field of molecular breeding. The invention provides a lycoris chinensis transcription factor LcNF-YB3. The amino acid sequence of the lycoris chinensis transcription factor LcNF-YB3 is as shown in SEQ ID NO: 1. The Lycoris chinensis transcription factor LcNF-YB3 delays plant flowering through forward regulation, the flowering time of an arabidopsis thaliana plant for heterologous expression of LcNF-YB3 is delayed, rosette leaves are increased, and the flowering time of the plant Lycoris chinensis is obviously advanced by silencing the LcNF-YB3 gene in Lycoris chinensis. The Lycoris chinensis transcription factor LcNF-YB3 can effectively regulate and control the flowering time, solves the problems of asynchronous flowering phases and the like in breeding, and provides a new genetic resource for the improvement of Lycoris and other bulb flower varieties.

The invention discloses a preparation method of recombinant catechol-2, 3-dioxygenase and an application of the recombinant catechol-2, 3-dioxygenase. According to the invention, a novel catechol-2, 3-dioxygenase group C23O927 is identified from a constructed metagenome library, and the catechol-2, 3-dioxygenase group C23O927 is a key enzyme for catalyzing degradation of polycyclic aromatic hydrocarbon pollutants. A C23O927-pET32a (+) recombinant expression vector is constructed and converted into host bacteria, heterologous expression of target protein is achieved, and the prepared recombinase belongs to acid enzymes and has good resistance to high temperature, acid, alkali, high-concentration metal ions, organic solvents and surfactants. The recombinase provided by the invention can be used in an acidic environment, has very good enzymatic activity, can catalytically degrade various catechol compounds, can be better used for treating polycyclic aromatic hydrocarbon polluted environments, and has important significance for developing more products which can tolerate various extreme environments and efficiently catalyze degradation of polycyclic aromatic hydrocarbons.

The invention provides an application of a Ustilaginoidea virens UvWSC1 gene in improvement of plant disease resistance. The invention develops a new application of the Ustilaginoidea virens UvWSC1 gene in improving the broad-spectrum disease resistance of crops such as rice for the first time, and the UvWSC1 gene is subjected to heterologous high expression in the rice, so that the broad-spectrum resistance of the rice to various pathogenic bacteria such as Ustilaginoidea virens, Magnaporthe oryzae and Xanthomonas oryzae can be obviously enhanced, and the agronomic traits of the rice are not influenced; an important theoretical basis is provided for rice disease-resistant breeding. By heterologous expression of the UvWSC1 gene, broad-spectrum disease resistance can be safely and effectively endowed to crops, a broad-spectrum disease-resistant rice variety is obtained for production, and the broad-spectrum disease-resistant rice gene has great application prospects and economic values in the aspects of crop breeding disease resistance improvement, rice disease prevention and control and crop yield increase and pesticide reduction.

The invention discloses a construction method and application of a probiotic engineering bacterium EcNpAm targeting animal intestinal tracts and improving inflammation. According to the present invention, the heterologous expression of the immunomodulatory protein Amuc1100 is successfully achieved through the gene engineering technology by using the Escherichia coli Niss1917 (EcN) as the host and using the anaerobic inducible plasmid pnirBMisL as the expression vector, and the novel engineering bacterium EcNpAm suitable for the animal intestinal anaerobic environment is constructed; furthermore, the expression efficiency of the target protein is represented by fusion expression of green fluorescent protein (GFP). The engineering bacterium is applied to prevention and treatment of animal intestinal inflammation, and successfully realizes targeted delivery of therapeutic protein to intestinal tracts of mice. Experiments show that EcNpAm can effectively relieve typical symptoms such as weight loss, colon shortening, pathological injury, colitis and the like of mice induced by dextran sodium sulfate (DSS) and protect integrity and functions of an intestinal barrier structure.

The invention discloses a preparation method and application of a recombinant A-type botulinum toxin, and aims to industrially produce the recombinant A-type botulinum toxin by utilizing the preparation method of the recombinant A-type botulinum toxin provided by the invention. The method comprises the following steps: firstly, constructing genetically engineered bacteria capable of heterologously expressing a botulinum toxin A gene in host bacteria by virtue of a genetic engineering means, then accumulating recombinant botulinum toxin A in a strain by virtue of the genetically engineered bacteria through high-density fermentation, collecting fermented thalli, crushing and purifying to obtain the recombinant botulinum toxin A, and finally, preparing the recombinant botulinum toxin A by virtue of the recombinant botulinum toxin A. And adding an auxiliary poising agent and a protective agent to prepare a liquid agent or a freeze-drying agent to obtain the recombinant A-type botulinum toxin for injection. According to the technical scheme, the complete recombinant botulinum toxin A with the purity as high as 99.9% is obtained, the yield is as high as 7000000 U / L, and the complete recombinant botulinum toxin A has no obvious difference from natural botulinum toxin A in structure and function and can be applied to multiple fields such as medical treatment, medical beauty and military affairs.

The invention discloses a method for synthesizing alpha-arbutin through biotransformation, and belongs to the technical field of biochemistry. A gene cloning technology is utilized, sucrose phosphorylase Spase in leuconostoc mesenteroides and sucrose phosphorylase gtfa in bifidobacterium adolescentis are screened and found through a Deep Molecules and DLKcat algorithm on a Uniprot database, novopro is utilized for codon optimization, then the sucrose phosphorylase Spase and the sucrose phosphorylase gtfa are expressed on a plasmid vector PET-28a and are converted into an escherichia coli BL21 (DE3) strain, and the sucrose phosphorylase Spase and the sucrose phosphorylase gtfa in the bifidobacterium adolescentis are obtained. An engineering strain for heterologous expression of the gene is constructed by taking the gene as a chassis cell. According to the process, sucrose and hydroquinone are taken as co-substrates, and bioconversion is carried out under the action of sucrose phosphorylase from different sources to obtain alpha-arbutin.

This invention discloses a mutant of raw starch hydrolase with improved stability and its applications. Using α-amylase AmyZ2 as the starting enzyme, and through computer-aided design to clarify the mutation site, a mutant was heterologously expressed in Bacillus subtilis, resulting in an α-amylase with improved stability. When using raw corn starch as a substrate, the mutant exhibits 1.57 times the specific enzyme activity and 2 times the stability of the starting enzyme. While maintaining the specific enzyme activity, the mutant enzyme shows a significant improvement in thermostability. This mutant has potential application value in the production of starch sugars using raw corn starch as a substrate.

This invention relates to the fields of bioengineering and fermentation engineering, and discloses a genetically engineered *Streptomyces albopictus* strain that produces high levels of ε-polylysine and its fermentation production process. This genetically engineered strain uses *Streptomyces albopictus* strains acclimated to ε-polylysine tolerance as a chassis, and its genome integrates... ppc and dapf Through expression box, heterogeneous asd Expression cassettes, containing secretory signal peptides lysp Fusion expression cassettes and D404A / K499A point mutations pls Expression cassette. The fermentation process employs a two-stage pH control strategy, maintaining a neutral environment during the cell growth phase and adjusting to an acidic environment during product synthesis. This invention improves ε-polylysine yield through a synergistic strategy of enhancing precursor supply, constructing efflux detoxification channels, and increasing synthase activity; combined with an acidic fermentation process, it effectively inhibits product degradation, yielding a high-molecular-weight and highly uniform target product suitable for industrial production.

The invention discloses a method for increasing the fermentation yield of mernomycin A based on a reinforced chassis strain glycosyl donor. Specifically, in the heterologous expression process of a sirnomycin A biosynthetic gene cluster in a chassis strain Streptomyces albus J1074, a glycosyl donor synthesis module gene and a resistance gene (MaPBP) are introduced at the same time, and on the basis of improving a glycosyl biosynthetic donor, the physiological tolerance of the chassis strain is also enhanced. Compared with a high-yield strain Streptomyces albus LX03 (CGMCC NO. 20985) of which the tolerance is only optimized, the yield of the strain Streptomyces albus LX02: pJQK610 subjected to genetic engineering optimization is improved by 285%, and the yield reaches 114 mg / L. The strain disclosed by the invention has the advantages that the yield of the strain Streptomyces albus LX02: pJQK610 is improved by 285%, and the yield of the strain Streptomyces albus LX02: pJQK610 is improved by 285%. The invention provides a high-yield technology for improving heterologous expression of the mernomycin A through collaborative optimization of precursor supply and physiological tolerance, and provides reference for efficient production of the medicine.

The invention discloses a biosynthesis method and application of cannabinoid compounds. The specific method comprises the following steps: constructing a non-reductive polyketide synthase (NRPKS) AtnG from a fungus Arthrinum sp.NF2194, an isopentenyl transferase NphBV49W / Y288P from an actinomycetes Streptomyces sp.CL190, a cyclase Svz9 from an actinomycetes Streptoviensis NA431, a GPP synthase AgGPPS from a plant Abis grandis and a terpene synthesis enhancement path MEV into a heterologous expression vector, and sequentially introducing the heterologous expression vector into escherichia coli, so as to successfully realize the production of the cannabinoid compounds OA, CBGA and CBCA. The cannabinoid compound disclosed by the invention has important medical and industrial values.

The application discloses a beta-1,4-xylanase mutant and a construction method thereof, and comprises the following steps: constructing a beta-1,4-xylanase recombinant expression vector; introducing the recombinant vector pNZ8048-P5-XynA into a competent lactococcus lactis by using an electrotransformation technology to construct a wild-type expression vector; on the basis, designing and constructing a multi-site mutant recombinant plasmid by using a site-directed mutation method, wherein the eighth asparagine (Asn) of the beta-1,4-xylanase is mutated into tyrosine (Tyr), the 22nd serine (Ser) is mutated into proline (Pro), and the 59th alanine (Ala) is mutated into lysine (Lys); introducing the multi-site mutant recombinant plasmid into the competent lactococcus lactis to construct a heterologous expression strain of the mutant beta-1,4-xylanase (Mut-1); and stably obtaining the mutant xylanase beta-1,4-xylanase (Mut-1) with high activity by using a metal affinity chromatography (Ni 2+ ) method. The specific enzyme activity of the mutant reaches 1929.30±5.36 U / mg, and the optimal temperature is increased by 15 DEG C compared with that of the wild type.