1491 results about "Bioengineerings" patented technology

The invention discloses a formate dehydrogenase mutant and application thereof in catalytic synthesis of D-mannitol, and belongs to the technical field of bioengineering. According to the formate dehydrogenase mutant provided by the invention, the 18th-site glutamic acid of wild-type formate dehydrogenase with an amino acid sequence shown as SEQ ID NO.2 is mutated into proline, the 57th-site asparagine is mutated into glutamic acid, the 70th-site histidine is mutated into tryptophan, the 235th-site serine is mutated into threonine, and the 316th-site valine is mutated into threonine, so that the formate dehydrogenase mutant is high in enzyme activity and catalytic activity; the coenzyme circulation efficiency during the production of D-mannitol can be obviously improved, so that the yield of D-mannitol can be effectively improved. When the genetically engineered bacterium co-expressed by the formate dehydrogenase mutant and the mannitol dehydrogenase mutant is used for catalyzing 150 g / L fructose to produce D-mannitol, the yield of D-mannitol within 15 h can reach 140 g / L or above.

The invention discloses an arginine decarboxylase diaA enzyme mutant and application thereof in preparation of butanediamine, and belongs to the field of bioengineering. According to the invention, rational charge overturning transformation is simultaneously carried out on a pentamer meridian oligomeric interface and a dimer latitudinal oligomeric interface, so that stable assembly and efficient catalysis of the decamer under the condition of neutral to alkaline pH (7.0-9.0) are realized. Wherein positive charges are introduced into a meridian interface to weaken electrostatic repulsion, and negative charges are introduced into a latitudinal interface to enhance dimer compactness and substrate transfer efficiency. The specific enzyme activity of the representative double mutant AdiAD110K / H736E at pH 8.0 is about 35 times that of a wild type, and the representative double mutant AdiAD110K / H736E keeps a complete decamer state in a pH range of 7.0-9.0. The yield of butanediamine is up to 145.9 g / L under the whole-cell catalysis of the mutant.

The invention discloses a rational copolymerization strategy for improving the stability of an oligomeric structure of acid-induced high-order oligomeric decarboxylase AdiA in a neutral to alkaline environment and application of the rational copolymerization strategy, and belongs to the field of bioengineering. According to the strategy, rational charge overturning transformation is carried out on a pentamer radial oligomeric interface and a dimer weft-wise oligomeric interface at the same time, and stable assembly and efficient catalysis of a decamer under the condition that the pH value is from 7.0 to 9.0 from neutral to alkaline are achieved. Wherein positive charges are introduced into a meridian interface to weaken electrostatic repulsion, and negative charges are introduced into a latitudinal interface to enhance dimer compactness and substrate transfer efficiency. The specific enzyme activity of the representative double mutant AdiAD471K / E467K / H736E is 45.5 times that of a wild type when the pH value is 8.0, and the representative double mutant AdiAD471K / E467K / H736E keeps a complete decamer state when the pH value is 7.0-9.0. The yield of butanediamine is up to 156.5 g / L by using the mutant to catalyze whole cells.

The invention discloses humanized III-type collagen as well as a preparation method and application thereof, and belongs to the technical field of bioengineering. According to the method, firstly, on the basis of an original humanized III-type collagen gene, cell adhesion activity is taken as an evaluation index, a better cell adhesion sequence is screened out and spliced and integrated with the original collagen gene, and brand-new humanized III-type collagen is obtained. And constructing a recombinant expression vector of the humanized III type collagen containing the adhesion sequence by taking the probiotic EcN as a host cell, and introducing the recombinant expression vector into the EcN to obtain a strain of functional recombinant probiotic. Compared with a traditional escherichia coli engineering bacterium BL21 (DE3), the recombinant probiotics have good cell adhesion activity while efficiently expressing the humanized type III collagen, the bacterial endotoxin content of the recombinant humanized type III collagen obtained through purification meets the industrial standard, and the recombinant probiotics have good application prospects. The purification cost caused by industrial removal of endotoxin can be avoided, so that the production cost is reduced, and the method has a good application prospect.

The invention is applicable to the technical field of bioengineering, and provides a coding gene for enhancing iron deficiency stress tolerance of plants and application. According to the soybean GmMYB14 transcription factor disclosed by the invention, the problem that the growth of soybeans is limited in an iron-deficient environment, particularly calcareous soil and soda saline alkali soil, is solved by excavating and applying the encoding gene (the nucleotide sequence is shown as SEQ ID No.1) of the soybean GmMYB14 transcription factor. Experiments prove that after the gene is over-expressed in arabidopsis thaliana and soybean, the tolerance of plants to iron deficiency stress can be remarkably enhanced. The invention provides a key gene resource for molecular breeding: the GmMYB14 effectively promotes the absorption and utilization of plants on iron by regulating and controlling the metabolic pathway of phenylpropane, not only can improve the planting adaptability of soybeans in low-iron soil, but also can improve the yield and quality of the soybeans, provides powerful technical support for enlarging the planting area of the soybeans in iron-deficient soil regions, and has a wide application prospect. The method is of great significance in relieving insufficient soybean productivity in China and improving the self-sufficiency rate.

The invention belongs to the technical field of bioengineering and artificial intelligence crossing, and particularly discloses a microbial fermentation experiment intelligent design method and system based on a large language model (LLM). According to the invention, a historical database can be automatically retrieved and an experiment resource state can be inquired according to an experiment purpose input by a user intention, an experiment scheme is generated through large language model reasoning, and a task structure which can be identified by an experiment system is synchronized to a digital system so as to support confirmation, optimization and execution of tasks.

The invention relates to a CHO-S cell strain capable of stably expressing H5N1 hemagglutinin protein and a construction method of the CHO-S cell strain, and belongs to the field of bioengineering.H5N1 hemagglutinin protein expression plasmids are obtained in an in-vitro synthesis and seamless cloning mode, 293T cells are transfected through the H5N1 hemagglutinin protein expression plasmids, and it is proved that the H5N1 hemagglutinin protein is expressed; the CHO-S cell strain capable of stably expressing the H5N1 hemagglutinin protein is obtained by transfecting CHO-S cells by using the H5N1 hemagglutinin protein expression plasmids and carrying out multiple rounds of cloning and screening, so that a basis is provided for obtaining H5N1 recombinant protein influenza vaccines.

The invention discloses preparation of a whey protein peptide mixture with immune and muscle-building effects, and relates to the technical field of food processing and bioengineering. The neutral protease is adopted and the pH is adjusted, so that the enzymolysis efficiency is effectively improved, and the enzymolysis time is greatly shortened; meanwhile, the whey protein peptide which is uniform in molecular weight distribution, free of peculiar smell and good in thermal stability is successfully prepared by accurately controlling enzymolysis conditions and combining microbial fermentation. The protein peptide can effectively improve thymus indexes and spleen indexes, enhance the proliferation capacity of splenic lymphocytes and the activity of NK cells, play an excellent immune regulation role and have a remarkable muscle building effect. The preparation process has the advantages of high efficiency, low cost, simplicity, convenience and the like, gives consideration to high quality and high functionality of the product, and has great application value.

The invention relates to the technical field of bioengineering, in particular to a recombinant VII type collagen for inhibiting scars as well as a preparation method and application of the recombinant VII type collagen. The amino acid sequence of the recombinant VII type collagen is as shown in SEQ ID NO. 1. The recombinant VII type collagen provided by the invention has a better cell adhesion function, so that the recombinant VII type collagen can be applied to the fields of preparation of tissue materials, wound dressings and the like. Meanwhile, the VII type collagen does not contain any tag or exogenous amino acid sequence, is a completely humanized sequence, and does not generate immune response. The VII type collagen has a good adhesion effect, the adhesion effect is better than that of other recombinant collagen, the adhesion effect is equivalent to that of a common cell adhesive in the market, scars can be reduced by inhibiting activation of a TGF-beta pathway, and the VII type collagen can be developed into skin care products and medical instruments for promoting traceless wound repair and has a wide application prospect.

The invention discloses an aspergillus niger recombinant bacterium AnCT-XynB-K-agdA and application thereof, and belongs to the technical field of microbiology and bioengineering. According to the invention, Aspergillus niger AnCat is taken as an expression host, firstly, an acid protease regulatory factor prtT is knocked out to obtain a defective strain, and then different chaperonins are subjected to fusion expression by optimizing integration sites of a laccase lcc9 expression cassette, so that the high-expression laccase chaperonin is obtained. According to the method, an expression vector pC3-5 'agdA-PcitA-XynB-L-lcc9-hph-3' agdA is constructed, a recombinant bacterium AnCT-XynB-K-agdA is further obtained, the enzyme activity of the extracellular laccase subjected to shake flask fermentation reaches 1821.2 U / L, and finally, the recombinant efficient expression of the laccase Lcc9 in aspergillus niger is realized.

The invention belongs to the technical field of bioengineering, and particularly relates to leuconostoc mesenteroides subsp. Mesenteroides FTCM002 and application thereof in preparation of dendrobium officinale leavening with the effects of reducing blood sugar, nourishing the stomach and resisting inflammation. Dendrobium officinale is subjected to enzymolysis and inoculated with the strain for fermentation, and the obtained fermented dendrobium officinale has the effect of inhibiting alpha-glucosidase; the gastric mucosal injury can be relieved, the expression of VEGF, IL-6, IL-8 and TNF-alpha in the gastric mucosal injury is reduced, and the effect of nourishing the stomach is achieved; the cell phagocytic rate can be increased, the NO concentration and the content of immune factors IL-6 and TNF-alpha can be increased, and the effect of enhancing the immunity is achieved; the expression quantity of IL-6, IL-1beta and TNF-alpha in inflammatory cells can be reduced, and the anti-inflammatory effect is achieved.

The invention discloses a bispecific nano antibody targeting CXCL1 and PD-L1 and application thereof, and belongs to the technical field of antibody engineering and bioengineering. The bispecific nano-antibody targeting CXCL1 and PD-L1 comprises at least one nano-antibody for recognizing a target CXCL1 and a nano-antibody for recognizing a target PD-L1, and nano-antibody monomers are connected through a linker. The bispecific nano-antibody targeting PD-L1 / CXCL1 provided by the invention has a unique structure, so that the bispecific nano-antibody targeting PD-L1 / CXCL1 has specific recognition and binding capacities to CXCL1 and PD-L1, the affinity to CXCL1 reaches 1.08 nM, the affinity to PD-L1 reaches 1.09 nM, drug resistance of a patient to antibody treatment caused by immune escape can be effectively prevented, and the bispecific nano-antibody targeting PD-L1 / CXCL1 is suitable for more patients and has good clinical application prospects. And a new thought is provided for CRC treatment.

The invention discloses construction and application of an escherichia coli L-tryptophan biosensor, and belongs to the technical field of bioengineering. The L-tryptophan biosensor provided by the invention comprises a mutated leader peptide fragment tnaC-tnaA, a promoter of the mutated leader peptide fragment tnaC-tnaA, a green fluorescent protein coding gene eGFP and a pTrc99a plasmid skeleton, a recombinant strain containing the L-tryptophan biosensor is cultured, the expression of green fluorescent protein in a culture solution is gradually enhanced along with the increase of the concentration of the L-tryptophan, and the fluorescence value of a unit cell shows better correlation when the concentration of the L-tryptophan is 0-1.5 g / L; therefore, when the biosensor is used for detecting the L-tryptophan in the fermentation liquor, the biosensor has the characteristics of simplicity in operation, sensitive response and high threshold value.

The invention discloses a GmbZIP36 protein related to aluminum resistance of plants in acid soil as well as a coding gene and application of the GmbZIP36 protein, and belongs to the technical field of bioengineering. The amino acid sequence of the GmbZIP36 protein is shown as SEQ ID NO: 2, 3 or 4, and the nucleotide sequence of the coding gene of the GmbZIP36 protein is shown as SEQ ID NO: 1. The invention finds that the expression of the GmbZIP36 gene is induced by aluminum stress, the relative root elongation and root biomass of arabidopsis thaliana and soybean under the aluminum stress can be obviously improved by over-expressing the gene in a plant, and aluminum accumulation is reduced, so that the aluminum resistance of the plant is enhanced. The invention provides a recombinant vector containing the gene, a host cell and application of the recombinant vector and the host cell in regulating and controlling the aluminum resistance of plants. Meanwhile, the invention also provides a method for producing an aluminum-resistant transgenic plant by using the gene, a kit for detecting the gene or protein and a method for carrying out assisted breeding by using the molecular marker linked with the gene. The invention provides a key gene resource for aluminum-resistant molecular breeding of crops, and has important significance for cultivating new varieties of crops adapting to acid soil.

The invention discloses an application of cryptotanshinone in preparation of an anti-mycobacterium tuberculosis drug, and relates to the technical field of bioengineering. The molecular formula of the valerianin disclosed by the invention is C19H20O3. The mycobacterium tuberculosis is a mycobacterium tuberculosis H37Rv strain. Cryptotanshinone is disclosed as a natural-source compound for the first time, has the dual advantages of high efficiency and low toxicity, has an obvious effect of resisting mycobacterium tuberculosis, provides a brand new candidate drug scheme with development potential for solving the difficulty of tuberculosis treatment, and has great scientific value and application prospect.

The invention discloses recombinant IV-type collagen as well as a preparation method and application thereof, and belongs to the technical field of bioengineering. The amino acid sequence of the recombinant IV type collagen comprises a plurality of repetitive units, and the repetitive units are shown as SEQ ID NO. 1. The recombinant IV type collagen fragment is derived from human IV type collagen, heterologous amino acid residues are not introduced, and rejection and sensitization risks are avoided; meanwhile, the hydrogel also has good biological activity, including cell proliferation promoting activity and cell adhesion promoting activity, and is good in biocompatibility. In addition, the preparation method of the recombinant IV-type collagen is simple and easy to operate, and the recombinant IV-type collagen with high purity and stability can be obtained through the fermentation and purification method. Therefore, the recombinant IV type collagen disclosed by the invention has a relatively good application prospect.

The invention belongs to the technical field of bioengineering medicines, and particularly relates to a gel dressing for repairing skin wounds and a preparation method of the gel dressing. The anti-fouling coating is prepared from the following raw materials in parts by weight: 65 to 75 parts of polyvinyl alcohol, 14 to 20 parts of sodium alginate, 4 to 8 parts of sodium carboxymethyl cellulose, 1 to 3 parts of sodium hyaluronate, 12 to 22 parts of glycerol, 1 to 3 parts of surface anti-fouling additive, 6 to 10 parts of antibacterial microcapsule and 2 to 2.8 parts of compound ion. According to the invention, a PVA freeze-thaw physical network and an alginic acid Ca / Zn composite ion network cooperate to limit a pore channel, so that stable forming is realized; a chitosan / sodium tripolyphosphate microcapsule is prepared from polyhexamethylene biguanide hydrochloride and covered with sodium alginate, release sensitive to pH / ionic strength, acceleration in an inflammation stage and self-limiting in a later stage are constructed, and long-acting bacteriostasis is formed by SA-Zn site slow release; the stability and staged adaptation are highlighted through processes such as encapsulation, low-shear doping and the like and raw material synergy.

The invention discloses a novel biosynthesis path for producing 3 '-phosphoadenosine-5'-phosphosulfuric acid and application, and belongs to the technical field of bioengineering. According to the invention, through recombinant expression and purification of ribose kinase, ribose phosphate pyrophosphate kinase, ribose phosphate transferase, adenine thiotransferase, adenosine phosphate sulfate kinase and polyphosphate kinase 2, a six-enzyme cascade reaction taking ribose and adenosine as substrates in vitro is constructed, the molar conversion rate reaches 22.85%, and the escherichia coli and bacillus subtilis PAPS cell factory can be used for preparing the recombinant ribose phosphate pyrophosphate kinase, the ribose phosphate transferase, the adenine thiotransferase, the adenosine phosphate sulfate kinase and the polyphosphate kinase 2. The yield of PAPS in a 5-L fermentation tank reaches 7.60 g / L and 5.03 g / L respectively. The PAPS synthesis route provided by the invention provides an extensible, economical and efficient solution for the production of sulfated compounds.

The invention belongs to the technical field of bioengineering, and relates to a transaminase mutant, a recombinant genetically engineered bacterium and application of the transaminase mutant in catalytic synthesis of (R)-1-Boc-3-aminopiperidine.The transaminase mutant is obtained by conducting single-point or combined mutation on the 131 site and / or the 197 site of an amino acid sequence shown in SEQ ID NO.2; the mutation sites comprise that the 131 phenylalanine is mutated into aspartic acid, threonine or tyrosine, and / or the 197 lysine is mutated into arginine or leucine. Experimental results show that compared with wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants, especially single-point mutants MyTA1-F131Y and MyTA1-K197R and a combined mutant MyTA1-F131Y-K197R, are all remarkably improved, and compared with the wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants are all remarkably improved. The mutant MyTA1-F131Y-K197R can be used for efficiently catalyzing asymmetric amination of N-Boc-3-piperidone to synthesize (R)-1-Boc-3-aminopiperidine, the conversion rate of the (R)-1-Boc-3-aminopiperidine after the (R)-1-Boc-3-aminopiperidine reacts for 24 hours under the condition that the substrate concentration is 100 g / L can reach 90% or above, and the mutant MyTA1-F131Y-K197R has a good industrial application prospect.

The invention belongs to the technical field of bioengineering, and particularly relates to a zearalenone toxin degrading enzyme variant and application thereof. The amino acid sequence of the zearalenone toxin degrading enzyme is as shown in SEQ ID NO.2, or the zearalenone toxin degrading enzyme with the amino acid sequence as shown in SEQ ID NO.2 is obtained through amino acid mutation. The zearalenone toxin degrading enzyme mutant is obtained through mutation screening, and compared with a wild type, the zearalenone toxin degrading enzyme mutant has the advantages that the zearalenone degrading capability is obviously improved; besides, the zearalenone toxin degrading enzyme is expressed by using alfalfa, the zearalenone toxin degrading enzyme with biological activity is easy to obtain, and the zearalenone toxin degrading enzyme has certain application potential in prevention and treatment of animal poisoning caused by zearalenone toxin pollution in agriculture and animal husbandry production.

The invention provides a system and a method for screening Cas protein mutants capable of identifying different PAM sequences, and belongs to the technical field of bioengineering. The system comprises a Cas protein mutant screening vector and an sgRNA expression vector, the Cas protein mutant screening vector comprises the following expression elements: a Cas protein coding gene, a plasmid replicon and a first resistance screening tag expression cassette; the sgRNA expression vector comprises the following expression elements: a plasmid replicon, a second resistance screening tag expression cassette, a third resistance screening tag expression cassette and an sgRNA expression cassette. According to the system and the method, aiming at the problem that the efficiency of identifying PAM sequences except NGG by wild type spCas9 protein is low, an active Cas9 mutant capable of identifying PAM sites except NGG is screened out, and the application field and the editing efficiency of a CRISPR gene editing system can be greatly expanded.

The invention discloses an intelligent cooperative regulation and control method and system for dissolved oxygen in a haematococcus culture solution, relates to the field of bioengineering, and controls a decision-making layer to dynamically switch between a growth promotion regulation and control mode and a stress induction regulation and control mode based on biomass data and physiological status data in a haematococcus culture stage so as to realize cooperative regulation and control of dissolved oxygen, illumination, pH and a carbon source. According to the method, a growth promotion mode and a stress induction mode are dynamically switched, biomass accumulation is promoted through dissolved oxygen sine wave pulse fluctuation in the vegetative period, astaxanthin synthesis is induced through high-oxygen and low-oxygen circulation and blue light regulation in the stress period, and compared with traditional static regulation, the biomass is increased, and the yield of astaxanthin is increased. A light-oxygen synergistic factor k is introduced to dynamically adjust the fluctuation range of dissolved oxygen, the problem of illumination-dissolved oxygen mismatching is solved, and the photosynthetic efficiency is improved; a stress intensity index SI is established, stress parameters are adaptively optimized based on the astaxanthin synthesis rate, cell damage caused by over-stress is avoided, and the stability of the astaxanthin synthesis rate in the stress period is improved.

The invention discloses a method for improving the synthesis level of L-tryptophan in escherichia coli based on ARTP mutagenesis high-throughput screening, and belongs to the technical field of bioengineering. According to the invention, the L-tryptophan biosensor pSensor-trp3 is constructed, and the L-tryptophan biosensor pSensor-trp3 is good in response under the condition that the exogenous addition concentration range of L-tryptophan is 0-300mg. L <-1 >. High-throughput screening is performed by using a flow cytometry, a dominant mutant strain YB-2 is obtained through iterative mutagenesis, and the shake flask L-tryptophan yield and the sugar-acid conversion rate of the dominant mutant strain YB-2 are 5.68 g.L <-1 > and 0.103 g.g <-1 > respectively and are increased by 11.4% and 10.7%. Through second-generation whole genome re-sequencing comparative analysis, it is speculated that the genes ynfB and waaO possibly have a promoting effect on synthesis of L-tryptophan. The L-tryptophan biosensor used in the invention also provides reference for high-throughput screening and transformation of other related L-tryptophan production strains.

The invention belongs to the technical field of bioengineering, and discloses a sunflower seed peptide for regulating metabolism of brain cells, the sunflower seed peptide has a biological sequence of Arg His Ala Lys Thr Pro Ser Asn Lys, and a preparation method of the sunflower seed peptide for regulating metabolism of brain cells comprises the following specific steps: S1, raw material pretreatment; s2, peeling and crushing; s3, protein extraction; s4, performing enzymolysis treatment; s5, performing enzyme deactivation treatment; s6, filtering and purifying; s7, concentrating and drying; and S8, quality detection and packaging. The sunflower seed protein is directionally decomposed into the active peptide fragment by precisely regulating and controlling compound protease and enzymolysis conditions, the active peptide fragment can be compatible with a brain cell specific receptor and penetrate through a blood brain barrier, and cell experiments and animal models prove that the peptide fragment can activate a mitochondrial respiratory chain complex, so that the mitochondrial membrane potential is increased by more than 30%, and the mitochondrial membrane potential is increased by more than 30%. Meanwhile, the activity of neurotransmitter synthetase can be enhanced, the brain health is protected, and tests further prove that the sunflower seed peptide also has the function of regulating the metabolism of brain cells.

The invention belongs to the technical field of biosynthesis, and particularly relates to an engineering bacterium for preparing stevioside through de novo fermentation as well as a preparation method and application of the engineering bacterium. According to the invention, mevalonate kinase in the MVA pathway is mutated and optimized. The method comprises the following steps: carrying out point mutation on mevalonate kinase MvK of a wild type source, constructing a stevioside synthesis route in an escherichia coli host, and comparing the influence of MvK mutation on the yield of stevioside, so as to determine a Q160L mutant, and applying the Q160L mutant to the stevioside production route to realize efficient production of stevioside.

The invention discloses a production strain for fermenting L-histidine and application of the production strain, and belongs to the technical field of biological engineering. According to the invention, escherichia coli E.coli CICC 10243 is taken as an original strain, histidine synthesis operon genes hisDCB-cg2302-cg2301-HA-impA-FI, hisN and hisEG from corynebacterium glutamicum are integrated on a genome of the escherichia coli E.coli CICC 10243, a pyruvate dehydrogenase AceE mutant coding gene is introduced, and an escherichia coli transcription factor SlyA coding gene slyA is inactivated. The novel strain E.coli His08 for fermentation production of L-histidine is prepared and fermented in a 5L fermentation tank for 60 h, the histidine yield reaches 58.39 g / L, the sugar-acid conversion rate is 0.15 g / g, and the strain E.coli His08 has important application value.

The invention discloses a method for preparing butanediamine and spermidine from whole cells, and belongs to the field of bioengineering. According to a rational copolymerization modification strategy, a meridian interface and a latitudinal channel interface of arginine decarboxylase are subjected to rational modification respectively or simultaneously, and a series of mutants are obtained. The optimal mutant AdiA H729D / E467K / H736E, which is subjected to double-interface synergistic modification, disclosed by the invention, keeps high activity in the whole neutral-alkaline range of pH (Potential of Hydrogen) of 7.0 to 9.0. The optimal pH of the arginine decarboxylase mutant is increased, the enzyme activity stability in a neutral pH range is improved, the arginine decarboxylase mutant is more suitable for the condition requirements of industrial microbial fermentation, and a foundation is laid for efficient synthesis of butanediamine. The spermidine yield is up to 153.3 mg / L by using the mutant to catalyze the whole cell.

The invention discloses a method for preparing butanediamine and spermidine by an enzyme method, and belongs to the field of bioengineering. The novel arginine decarboxylase mutant is successfully provided, the mutant shows excellent catalytic performance under the alkaline condition, and the specific enzyme activity of the mutant reaches 24.9 U / g and is improved by 8.3 times compared with that of wild type enzyme. The invention develops a two-step synthesis process based on the constructed arginine decarboxylase mutant, and the two-step synthesis process is used for efficiently preparing spermidine. Experimental results show that the process successfully realizes the remarkable increase of the yield of spermidine, and the final yield reaches 200.4 mg / L.

The invention belongs to the technical field of bioengineering and food safety, and particularly relates to a fusion enzyme for degrading aflatoxin B1 (AFB1) and / or zearalenone (ZEN) and application of the fusion enzyme. The fusion enzyme S1-AsDPP III disclosed by the invention can effectively degrade AFB1 and ZEN, the fusion enzyme is obtained by fusing a section of self-assembled amphiphilic oligopeptide S1 sequence at the N end of wild type AsDPP III, and the thermal stability of the fusion enzyme and the amphipathy of the fusion enzyme in an oil-water coexistence system can be remarkably improved. Under mild reaction conditions, the fusion enzyme can efficiently degrade AFB1 and ZEN in vegetable oil, and is especially suitable for detoxification treatment of common edible oil such as peanut oil and corn oil. The invention provides a green, safe and efficient scheme for removing fungaltoxin from grease food, and the method has a good industrial application prospect.

The invention discloses application of a gene GlZn2Cys661 in regulation and control of synthesis of ganoderic acid. The nucleotide sequence of the gene GlZn2Cys661 is as shown in SEQ ID NO. 1. The gene expression is regulated and controlled by constructing an overexpression or silent vector, so that the synthesis of the ganoderic acid is promoted or inhibited, and an effective method is provided for regulating and controlling the yield of the ganoderic acid. The invention relates to the technical field of bioengineering, and discloses an application of a gene GlZn2Cys661 in regulation and control of ganoderic acid synthesis. The invention provides a key gene target and a core engineering strain for efficiently producing ganoderic acid through a metabolic engineering means, and has important application value.