43results about How to "High molar conversion" patented technology

The invention discloses a method for preparing GABA (gamma-aminobutyric acid) by using a biotransformation method, and belongs to the technical field of preparation of GABA. The method comprises the following steps: adopting lactobacillus brevis CGMCC NO.3414 as an original strain; carrying out enrichment culture and thallus collection; resuspending the thallus in a scientifically compounded buffer solution of a mixture of L-sodium glutamate and glutamic acid; adding Na2B4O7.10H2O or MgSO4 having relatively strong activation for the endoenzyme generated by the strain, so as to enable the activity of endoenzyme to be maximally given into play; catalyzing and converting the mixture of L-sodium glutamate and glutamic acid into GABA, wherein the content of GABA in the conversion solution is 45.74-202.18 g/L, the molar conversion rate of the substrate is 95.92-99.75%, and the thallus can be repeatedly used for 8 times. According to the method, the product quality and yield are improved, the environment is protected, the method is relatively good in economic and social benefits and applicable to scale production, and industrial popularization is facilitated.

The invention belongs to the technical field of biocatalysis, and particularly relates to a method for improving steroid medicine production strain vitality to efficiently produce a steroid medicine precursor by fermentation. The method improves steroid medicine production strain vitality to efficiently produce a steroid medicine precursor by fermentation through the overexpression of type II NADHdehydrogenase gene, and solves the problems of long fermentation cycle and low production efficiency during the steroid medicine precursor production by a microbiological method. A new method for reducing production cost of steroid medicine precursor is provided.

The invention belongs to the technical field of biocatalysis, and particularly relates to a method for enhancing the steroid medicine precursor production by strengthening the intracellular NADH dehydrogenation of a steroid medicine production strain. The method introduces NADH dehydrogenase-NDH2 which has no proton-pump function and exists insteroid medicine production strain microorganisms, constructs a NDH2-enhanced steroid medicine precursor production strain to strengthen the dehydrogenation of NADH in the steroid medicine precursor production strain, solves a problems of long fermentation cycle and low production efficiency caused by excessive accumulation of NADH in the process of microbial transformation production of the steroid medicine precursor, and can help reduce energy consumption and save production cost in the production process of the steroid medicine precursor. The method can be effectively used for strengthening the intracellular NADH dehydrogenation of other industrial production strains, and has wide application value. A new method for reducing the production cost of steroid medicine precursor is provided.

The invention provides a method for preparing (S)-(+)-3-hydroxytetrahydrofuran by transforming engineering strains. The method is characterized in that the (S)-(+)-3-hydroxytetrahydrofuran is preparedby taking 3-ketotetrahydrofuran as a substrate, immobilizing thallus cells, which are obtained by fermenting genetically engineered bacteria escherichia coli LC001 and can provide an enzyme continuously, through calcium alginate into a biological catalyst, and carrying out catalytic reaction. The method for preparing the (S)-(+)-3-hydroxytetrahydrofuran by transforming the engineering strains, provided by the invention, has the advantages of convenience for operation, high yield, moderate reaction conditions, environment friendliness, high catalysis specificity, high catalysis efficiency, high substrate and product tolerance and low cost, and has potential value in industrialized production.

The invention belongs to the technical field of biocatalysis, and particularly relates to construction and application of genetically engineered bacteria for one-step conversion from cheap substrate phytosterol (PS) as a raw material to 5alpha-androstanedione (5alpha-AD). The 5alpha-reductase gene from treponema pallidum is heterologously expressed into mycobacteria mainly producing androstenedione (AD), and one-step biotransformation from phytosterol to 5alpha-AD is realized, so that green and efficient production of 5 alpha-AD is realized.

The invention provides a method for preparing S-(+)-3-methyl hydroxybutyrate through microbial transformation, which comprises the following steps that: in phosphate buffer solution with the pH value being 5.0 to 8.0, methyl acetoacetate is used as substrates, enzyme-containing strains obtained through fermenting saccharomyces cerevisiae CGMCC No. 2266 are used as microbial catalysts, conversion region is carried out for 8 to 40h at 25 to 45 DEG C, after the reaction is completed, and conversion liquid is prepared into the S-(+)-3-methyl hydroxybutyrate through separation and purification. The method provided by the invention has the main beneficial effects that 1. produced strains are safe and innoxious and are easy to be cultured in a large scale; 2. a large number of biological catalysts can be obtained, and the cost is low; 3. the reaction conditions are mild, and the environmental-friendly effect is realized; 4. the operation is simple and convenient, and the addition of coenzymes with a high price is not needed in the reaction process; and 5. the large-scale industrialized production is easy to realize, and the mol conversion rate is high.

The invention relates to a method for preparing r-4-chloro-3-hydroxybutanoate by utilizing coupling extraction of an enzyme membrane reactor. The method adopts the enzyme membrane reactor, an organicsolvent charging barrel and a substrate charging barrel, wherein filter membranes are distributed inside the enzyme membrane reactor, one side of the upper end of the enzyme membrane reactor is connected with a feed liquid outlet, one side of the enzyme membrane reactor is provided with an organic solvent outlet, one side of the lower end of the enzyme membrane reactor is connected with a feed liquid inlet, and the other side of the enzyme membrane reactor is provided with an organic solution inlet. The method is simple in process, the emulsification phenomenon in the reaction and extraction processes is decreased, the yield is improved, the loss of an organic solvent is reduced, multiple times of extraction are not needed, the operation is simple and convenient, the large-scale industrialproduction is facilitated, a product can be continuously collected, the inhibition of the product to enzyme or the toxicity of the product to cells is relieved, the molar conversion rate is improved,and thus the industrial production is facilitated.

The invention discloses a method for producing 1, 4-butanediamine by using recombinant escherichia coli, which belongs to the genetic engineering technology, and is characterized in that an arginine decarboxylase mutant and agmatine enzyme are successfully expressed by using a high-copy plasmid pXMJ19 to construct recombinant bacteria. Whole-cell transformation results show that the original bacteria do not have the capability of excessively accumulating 1, 4-butanediamine, and the recombinant bacteria can realize excessive accumulation of 1, 4-butanediamine; and meanwhile, based on the characteristic that the genetically engineered strain can excessively accumulate 1, 4-butanediamine, enzymatic conversion is successfully adopted to produce 1, 4-butanediamine by taking arginine as a substrate. IPTG (isopropyl-beta-d-thiogalactoside) is added in a cell culture process to induce enzyme expression, and magnesium ions and coenzyme pyridoxal phosphate are added in a transformation system according to enzymatic properties of the arginine decarboxylase. Finally, 72.6 g.L <-1 > 1, 4-butanediamine can be accumulated through 24-hour conversion, and the yield of agmatine serving as an intermediate product is 0.14 g/L.

The invention relates to an esterification conversion method of gulonic acid. The method comprises: uniformly mixing industrial methanol and concentrated sulfuric acid, adding a gulonic acid dry product in a stirring state, carrying out a methyl esterification reaction in a staged temperature changing manner, sequentially adding sodium bicarbonate and deionized water, heating, carrying out a conversion reaction, cooling after the reaction is finished, and carrying out centrifugal separation to obtain the sodium ascorbate. According to the invention, the gulonic acid esterification conversion method is simple in process, easy to operate, low in cost, capable of greatly increasing the molar conversion rate from gulonic acid to VC sodium (increased by 1.5-3.2% compared with the prior art) andsuitable for large-scale production.

The invention discloses a catalase mutant and application thereof. The mutant is mutated at least at one of the following positions of an initial catalase amino acid sequence: 67th isoleucine is mutated into phenylalanine, 102nd methionine is mutated into leucine, 200th valine is mutated into phenylalanine, and 251st alanine is mutated into serine, and the initial catalase amino acid sequence is shown as SEQ ID NO.1. The invention further discloses a preparation method of the mutant. Compared with initial catalase BmCAT, the amino acid sequence of the catalase mutant is replaced, and the formed mutant remarkably improves the capability of catalyzing hydrogen peroxide. In the process of biosynthesizing pyruvic acid by using lactate oxidase, hydrogen peroxide generated in the reaction process is eliminated by using whole-cell catalysis for expressing the catalase mutant, the use amount of enzyme is small, the elimination rate of hydrogen peroxide is remarkably improved, the maximum molar conversion rate of the product pyruvic acid is 99.7%, and the method has a very high industrial application prospect.

The invention discloses a chemical synthesis method of (R)-2-phenoxypropionic acid. The chemical synthesis method comprises the following steps: performing diazotization and chlorination on L-alanineserving as a starting material to obtain (S)-2-chloropropionic acid; then carrying out an etherification reaction to obtain (R)-2-phenoxypropionic acid ((R)-PPA). According to the method, diazotization and chlorination are performed on L-alanine serving as the starting material to obtain (S)-2-chloropropionic acid, and then the etherification reaction is carried out to obtain the (R)-PPA, whereinthe molar conversion rate of (R)-2-phenoxypropionic acid is up to 92.45 percent. The chemical synthesis method of the (R)-PPA is proposed for the first time, and has the advantages of cheapness and easy availability of raw materials, simple process and higher product purity and the like.