11 results about "Xylose Reductase" patented technology

The invention relates to the technical field of enzyme engineering, in particular to a xylose reductase XR21 mutant and application thereof. Specifically, the invention provides a novel xylose reductase mutant aiming at the defect of poorer thermal stability of the existing wild type xylose reductase, and particularly provides a xylose reductase mutant which is obtained by performing single or multiple site amino acid mutation on the 19th site, the 48th site, the 79th site, the 208th site and the 300th site of a xylose reductase sequence shown as SEQ ID NO: 2, compared with wild type xylose reductase, the obtained xylose reductase mutant has the advantages that the activity of catalyzing an epimer substrate arabinose into arabitol can be obviously reduced, and meanwhile, the selectivity to xylose is improved, so that the operation process of downstream separation and purification is simplified, and the biological catalysis requirement of green industry is met.

The invention relates to the technical field of enzyme engineering, in particular to a xylose reductase XR31 mutant and application thereof. Specifically, the invention provides a novel xylose reductase mutant aiming at the defect of poor thermal stability of the existing wild type xylose reductase (SEQ ID NO: 2), and particularly provides a xylose reductase mutant which is obtained by performing single or multiple site amino acid mutation on the 21st site, the 46th site, the 128th site, the 168th site and the 205th site of a xylose reductase sequence shown as SEQ ID NO: 2, compared with wild type xylose reductase, the obtained xylose reductase mutant has the advantages that the catalytic activity and the thermal stability on substrate xylose are obviously improved, the xylose reductase mutant can stably work under a high-temperature condition, and substrate conversion in industrial application is more efficiently realized.

The invention provides a strain for producing beta-carotene as well as a construction method and application of the strain, and belongs to the technical field of synthetic biology and genetic engineering. The construction method of the MYy107 strain disclosed by the invention comprises the following steps: step 1, integrating a mevalonate kinase gene ERG12, a phosphomevalonate kinase gene ERG8, a mevalonate diphosphate decarboxylase gene ERG19 and an isopentene diphosphate isomerase gene IDI1 on an RT08 bacterium, so as to obtain an RT10 strain; 2, a xylose reductase gene XYL1, a xylitol dehydrogenase gene XYL2, a xylose isomerase mutant XylA3 * and a xylulokinase gene Yl.Xk are integrated on the RT10 strain, and the MYy107 strain is obtained. According to the MYy107 strain constructed by the invention, the beta-carotene can be produced by using xylose and acetic acid at the same time, and the yield of the beta-carotene is remarkably improved and reaches 710.01 mg / L.

The invention discloses recombinant escherichia coli for producing D-tagatose by using redox enzyme driven by cofactor regeneration as well as a construction method and application of the recombinant escherichia coli, and belongs to the technical field of biological engineering. The method comprises the following steps: introducing xylose reductase xyrB, glucose dehydrogenase Gox2015, galactitol dehydrogenase RlGDH mutant T193G / G98C and water-producing NADH oxidase SpNox into escherichia coli, so as to construct recombinant escherichia coli; according to the method disclosed by the invention, a way for synthesizing the D-tagatose by regenerating and driving oxidoreductase through cofactors is designed and constructed, and lactose in whey can be completely converted into the D-tagatose and sodium gluconate by combining the way with beta-galactosidase, so that high-valued utilization of a dairy product processing by-product whey is realized.

The application discloses a genetically engineered bacillus subtilis for producing porphyra-334, a kind of bacteriosporin amino acid, and a construction method and application thereof, and belongs to the field of microbial metabolic engineering and synthetic biology.The strain takes bacillus subtilis WB600 as a starting bacterium: 1) a competitive pathway gene ywjH is knocked out to strengthen precursor supply;2) a gene cluster NlmysABCD derived from a porphea lincolnii is integrated in multiple copies to enhance pathway flux;3) sporulation genes spo0A and spoIIIE and threonine degradation gene tdh are knocked out to block byproduct generation and redistribute metabolic resources;4) xylose metabolism genes xylAB are introduced.The yield of porphyra-334 of the engineered bacterium reaches 3.38 g / L in shake flask fermentation, and the yield is increased to 15.1 g / L in 50 L fermenter fed-batch culture.

This invention discloses a strain for the efficient synthesis of D-tagatose, its preparation method, and its applications. Through strategies such as the discovery of novel galactitol dehydrogenase and promoter engineering, this invention initially increased tagatose yield by 28.48%. Simultaneously, a highly efficient and sensitive tagatose biosensor was developed, which was used as a screening tool for xylose reductase. Ss XR molecularly modified the strain to obtain the F128M-Q219K double mutant, which achieved a tagatose yield of 5.39 g / L in the producing strain. Based on this, amino acid complementation optimization was performed on the high-yielding strain, and the final engineered strain achieved a tagatose yield of 44.61 g / L in a 5 L bioreactor. This study provides a new strategy and core technology support for the efficient biosynthesis of tagatose.

Provided herein are recombinant microorganisms having two or more copies of a nucleic acid sequence encoding a xylose isomerase, wherein the nucleic acid encoding the xylose isomerase is an exogenous nucleic acid. Optionally, the recombinant microorganism comprises at least one nucleic acid sequence encoding a xylulokinase and / or at least one nucleic acid sequence encoding a xylose transporter. The provided recombinant microorganism is capable of growing on xylose as a carbon source.

This invention discloses a genetically engineered Bacillus subtilis strain for producing Mycosporine-glycine, its construction method, and its applications. Starting with Bacillus subtilis WB600, this strain significantly enhances Mycosporine-glycine synthesis by knocking out the competing pathway gene ywjH and expressing the AvmysABC gene cluster from Anabaena polymorpha at multiple sites. Further knocking out the sporulation genes spo0A and spoIIIE and introducing the xylose metabolism gene clusters xylA-xylB, combined with a mixed carbon source fermentation strategy, significantly increased the yield. The engineered strain achieved a Mycosporine-glycine yield of 3.64 g / L in shake-flask fermentation and 15.8 g / L in a 50 L fed-batch fermenter.

The application discloses a method for synchronously and efficiently metabolizing mixed sugar based on a Pichia pastoris mixed flora and application thereof. The Pichia pastoris mixed flora comprises at least one Pichia pastoris engineering strain for xylose metabolism and one Pichia pastoris engineering strain for oligosaccharide metabolism. By means of functional division of the strains, the interference of glucose signal on the xylose metabolic pathway is physically and genetically isolated, and the synchronous metabolism of xylose and cellulosic oligosaccharide is realized. The metabolic burden of each strain is reduced, the exclusive pathway of each strain can be optimized, the pathway competition and the imbalance of auxiliary factors are avoided, the overall fermentation rate and the sugar conversion rate are improved. The mixed flora system has a certain buffering capacity to environmental fluctuations and is more stable than a single strain. The strategy is particularly suitable for complex lignocellulose hydrolysate, and can effectively solve the problem of asynchronous utilization of multiple fermentable sugars in the lignocellulose hydrolysate and improve the total utilization rate of raw materials. In the process of simultaneous saccharification and fermentation of the mixed flora, the utilization rate of xylose and cellulosic oligosaccharide is improved, and the integrated biorefinery cycle is shortened.

The invention belongs to the technical field of microbial genetic engineering and industrial fermentation, and discloses an aspergillus niger engineering strain for producing L-malic acid by using xylose and a construction method and application of the aspergillus niger engineering strain. A three-gene recombination strain of an XR gene for coding xylose reductase, an XDH gene for coding xylitol dehydrogenase and an XK gene for coding xylulokinase through simultaneous overexpression is obtained through directional construction. Through synergistic overexpression of the XR gene, the XDH gene and the XK gene, the limitation that the starting strain LH-1 cannot utilize the xylose is successfully broken through, and effective utilization and directional conversion of the xylose are realized. The strain can be used for producing L-malic acid by using a low-cost xylose raw material, so that the production cost is remarkably reduced, a new technical path is provided for industrial production of organic acid, and the strain has a wide industrial application prospect.

The invention relates to the technical field of enzyme engineering, in particular to a xylose reductase XR34 mutant and application thereof. Specifically, the invention provides a novel xylose reductase mutant aiming at the defect of low enzyme activity of the existing wild type xylose reductase, and particularly provides a xylose reductase mutant which is obtained by carrying out single or multiple site amino acid mutation on the 48th site, the 111st site, the 219th site, the 306th site and the 309th site of the xylose reductase sequence shown as the amino acid sequence SEQ ID NO: 2, compared with wild type xylose reductase, the obtained xylose reductase mutant has remarkably improved catalytic activity on substrate xylose, so that the production cost of xylitol can be reduced, and a new strategy and a new method are provided for efficient production of xylitol.