38 results about "Xylulose" patented technology

The invention relates to the technical field of preparation of high-added-value chemicals through chemical catalysis of catalysts, in particular to a preparation method, a product and application of a bimetallic MOF catalyst. The preparation method comprises the following steps: uniformly mixing zircon salt, tin salt, an organic ligand and an organic solvent to obtain a mixed solution; and heating the mixed solution for reaction to obtain a reaction solution, washing, carrying out solid-liquid separation, and drying the obtained solid to obtain the bimetallic MOF catalyst. The method is easy to operate and low in cost, is close to conditions of large-scale production and application, and has important practical value. The bimetallic MOF catalyst prepared by using the method disclosed by the invention enhances the Lewis acidity of the catalyst, effectively promotes isomerization conversion from xylose to xylulose and reverse aldol condensation from xylulose to a C3 intermediate product in a cascade reaction process, and improves the selectivity of a main reaction path for preparing lactic acid from biomass; and efficient catalytic conversion from biomass to lactic acid is realized.

The invention belongs to the technical field of xylulose production, and discloses a method for catalyzing hemicellulose to generate xylulose by an immobilized enzyme cascade reactor. According to the method, hemicellulose is used as a raw material, aminated macroporous resin Namberlyst-15 is used as a carrier, xylanase and xylose isomerase are subjected to cross-linking adsorption to obtain an immobilized double-enzyme Namberlyst-15-Xyn-XI cascade reactor, and the xylulose is produced by the immobilized double-enzyme Namberlyst-15-Xyn-XI cascade reactor. According to the method, efficient immobilization and recycling of xylanase and xylose isomerase are achieved, the catalytic efficiency and selectivity are improved, the problems of high raw material cost and poor enzyme stability in the xylulose production process are solved, technical reserve is provided for the xylulose production process, and meanwhile technical support is provided for construction of a high-stability enzyme cascade reactor.

The invention discloses recombinant Escherichia coli for producing xylitol by efficiently utilizing L-arabinose without adding glycerol and application, and belongs to the technical field of genetic engineering. Escherichia coli with an araBAD operon and an L-xylulokinase gene lyxK knocked out is used as a starting strain, a glucose specific transporter gene ptsG and a D-xylulokinase gene xylB in a genome are knocked out, and a global regulatory factor CRP is mutated; on the basis of an araA, dpe and lxr three-enzyme expression universal method reported at present, the gene arrangement sequence and copy number in three-enzyme tandem expression are optimized, a promoter and an RBS sequence are optimized and screened, and three-enzyme genes are integrated to a specific position of an escherichia coli chromosome in an optimized multi-copy form. According to the method, the inhibition effect of glucose on L-arabinose is achieved, the in-vivo multienzyme catalysis efficiency of existing synthesis of xylitol from arabinose is remarkably improved, and the yield of precursor arabitol and the yield of the product xylitol are greatly improved.

The invention relates to a method for characterizing intracellular NADPH (Nicotinamide Adenine Dinucleotide Phosphate) generation amount of yarrowia lipolytica through xylose consumption, and belongs to the technical field of biology. According to the method, the yarrowia lipolytica overexpressing xylose reductase, xylitol dehydrogenase and xylulokinase is inoculated into a culture medium taking xylose as a unique carbon source for culture, and a linear relation between the xylose consumption and the NADPH generation amount is established, so that the generation level of the NADPH can be represented by measuring the xylose consumption in the culture medium. The invention provides an effective method for characterizing the intracellular NADPH level of the yarrowia lipolytica, the intracellular NADPH level can be characterized only by detecting the consumption of xylose, and the detection method is simple and efficient.

The present invention belongs to the field of microbial technology, and relates to a genetically engineered bacterium for preparing ethanol based on hydrolyzed sugar from wood fiber and its application. The bacterium is a high xylose utilization and inhibitor tolerance engineered bacterium. The engineered bacterium is based on Saccharomyces cerevisiae S288C as a chassis strain, and co-expresses heterologous xylose reductase-xylitol dehydrogenase pathway-related genes, xylose transport-related genes, xylose isomerase-related genes and xylose isomerase genes, and over-expresses endogenous xylulose kinase-related genes, non-oxidative pentose phosphate pathway-related genes, reduced glutathione system genes, superoxide dismutase expression system-related genes, NADPH / NADP + The genes and transcription factors related to the cofactor circulation system were knocked out, the genes related to the competitive metabolic pathway were knocked out, and the bacteria were domesticated with sugar sources and inhibitors as pressure; the engineered bacteria can efficiently metabolize xylose and produce high-concentration ethanol in non-detoxified lignocellulose hydrolysate with high inhibitor concentrations and without any nutrient salt addition.

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 relates to an aerobic methanophilic engineering bacterium for producing taxadiene as well as a construction method and application of the aerobic methanophilic engineering bacterium. A strong promoter P16200 is used for expressing a taxadiene synthase gene TXS in host bacteria; 1-deoxy-xylulose-5-phosphate synthase genes dxs1 and dxs2, geranyl pyrophosphate synthase gene ispA and isopentenyl pyrophosphate isomerase gene Bsidi from bacillus subtilis in a taxadiene synthesis route are overexpressed, the metabolic flux of the route in which a target product is located is improved, meanwhile, 6-glucose phosphate dehydrogenase zwf1 is overexpressed, supply of NADPH (nicotinamide adenine dinucleotide phosphate) is enhanced, and the yield of the target product is increased. Therefore, the material flow and the reducing power are synergistically enhanced; bioconversion from methane to taxadiene is achieved for the first time, the yield of the taxadiene of the constructed engineering methanophilic bacteria is obviously increased, the engineering methanophilic bacteria have industrial application prospects, and a new way is provided for efficient synthesis of terpenoids.

The invention belongs to the technical field of biological enzyme engineering, and particularly relates to a D-psicose 3-epimerase mutant derived from rumen clostridium and application of the D-psicose 3-epimerase mutant. The mutant disclosed by the invention is obtained through specific single-point mutation on the basis of a wild type amino acid sequence of D-psicose 3-epimerase, and specifically, the mutant is obtained through mutation of the following five sites: L159V, Q164E, N238T, E288G and C289I; wherein mutants containing all five single point mutations are named as XT mutants. The mutants significantly improve the thermal stability of the enzyme and the catalytic conversion rate under high substrate concentration, especially under the high substrate concentration of 300-700 g / L, the conversion rate of D-psicose of the XT mutant is improved by 2-3% compared with that of a wild type, and the thermal stability of the XT mutant is improved by 28 times compared with that of the wild type. The mutant is suitable for a high-temperature and high-substrate-concentration industrial conversion system, the production cost of D-psicose can be remarkably reduced, and the mutant has important industrial application value.

The invention relates to a recombinant pichia pastoris strain for producing coupled xylitol by NADPH (nicotinamide adenine dinucleotide phosphate) dependent growth and a construction method of the recombinant pichia pastoris strain, and belongs to the technical field of microbial fermentation. The recombinant pichia pastoris strain provided by the invention contains an NADPH dependent xylitol dehydrogenase gene, a sugar phosphatase gene, a D-arabinol-4-dehydrogenase gene, a fructose-1, 3, 4-triazole-1, 3, 4-triazole-1, 3-triazole-1, 3-triazole-1, 3-triazole-1, 3- The gene sequence is as follows: a 1, 6-diphosphatase gene, a phosphoketolase gene, a phosphate transacetylase gene, a glucose-6-phosphate dehydrogenase gene, a 6-phosphogluconolactonase gene, a 6-phosphogluconate dehydrogenase gene and a ribulose-5-phosphate epimerase gene; gene for expressing xylulokinase is knocked out or down-regulated: NADH dependent type xylitol dehydrogenase gene, ribose-5-phosphate isomerase gene, glutamate dehydrogenase gene, phosphofructokinase gene and phosphoglucose isomerase gene. The yield of xylitol produced by fermentation of the strain is far higher than that in the prior art.

The invention belongs to the technical field of synthetic biology, and particularly relates to recombinant escherichia coli for efficiently biosynthesizing lanosterol as well as a construction method and application of the recombinant escherichia coli. The method comprises the following steps: introducing exogenous squalene synthase (SQS), squalene epoxidase (SE) and oxidized squalene cyclase (OSC) genes into escherichia coli to construct a complete lanosterol synthesis route; the method comprises the following steps of: enhancing MEP pathway rate-limiting enzymes, namely 1-deoxy-D-xylulose-5-phosphate synthase (DXS), isopentenyl pyrophosphate isomerase (IDI) and farnesyl pyrophosphate synthase (FPS), so as to increase precursor supply, and further regulating and controlling the expression of key enzyme genes by adopting an arabinose promoter (PBAD). The lanosterol yield of the constructed engineering bacterium BW-2 reaches 8.02 mg / L and is increased by 40 times compared with that of an initial strain, and a brand new technical scheme is provided for green and efficient industrial production of lanosterol.

The invention discloses a method for synthesizing xylitol by catalyzing D-xylose through a multi-enzyme system and a special engineering bacterium thereof. The invention provides a method for synthesizing xylitol from D-xylose, which specifically comprises the following steps: taking D-xylose as a substrate, generating xylulose under the catalysis of xylose isomerase, and generating xylitol under the action of xylulose reductase. For the production of xylitol, huge economic benefits can be generated, and the method has great popularization and application values.

The application discloses high-yield gernien A engineering methanotrophs, a construction method and application thereof, and belongs to the technical field of metabolic engineering and synthetic biology. P mxaF expressing a gernien A synthase encoding gene gas overexpressing a 1-deoxy-xylose-5-phosphate synthase encoding gene in a gernien A synthesis pathway dxs1 and dxs2 a farnesyl pyrophosphate synthase encoding gene ispA a isopentenyl pyrophosphate isomerase encoding gene Bsidi simultaneously overexpressing 6-phosphogluconate dehydrogenase zwf1 and pfk1 and fba2 in an EMP pathway, to obtain gernien A engineering methanotrophs. The fermentation production of gernien A is carried out by using the engineering methanotrophs, and the yield of gernien A is obviously improved, so that the engineering methanotrophs have an industrial application prospect.

The invention provides a method for efficiently preparing L-xylulose by controlling configuration inversion based on a two-step enzymatic method and application of the method, and belongs to the technical field of bioengineering. According to the invention, two key enzymes 2-PsXDH and 4-PaXDH capable of mediating directional conversion of D-xylulose into L-xylulose are determined through in-vitro screening and catalytic verification, and a system for efficiently preparing L-xylulose by controlling configuration inversion is constructed based on a two-step enzymatic method. The method for efficiently preparing L-xylulose based on two-step enzymatic control of configuration inversion is constructed by using the system, the method can directionally regulate and control configuration inversion to synthesize L-xylulose, the problems of isomer pollution and the like in chemical synthesis can be effectively solved, subsequent separation and purification of products are greatly facilitated, and the method is suitable for industrial production. Good industrial application potential is realized; the preparation method of the L-xylulose is simple, can be used for catalyzing D-xylulose to convert into the L-xylulose in vitro or in vivo, and has good practicability.

There is provided an aqueous personal care rinse-off formulation, the aqueous personal care rinse-off formulation comprising: a dermatologically acceptable aqueous vehicle; a dermatologically acceptable cleansing surfactant, wherein the dermatologically acceptable cleansing surfactant comprises an anionic surfactant; and an alkyl polysaccharide thickener; wherein the alkyl polysaccharide thickener comprises from 50% to 100% by weight, based on the weight of the alkyl polysaccharide thickener, of a linear alkyl polysaccharide of formula (A), R-O-(S) nH (A) wherein R is a linear C9-15 alkyl group; wherein n is an average value from 1 to 2.5; wherein S is a monosaccharide selected from the group consisting of ribulose, xylulose, ribose, arabinose, xylose, lyxose and mixtures thereof; and wherein 70% to 100% by weight, based on the weight of monosaccharide S in the linear alkyl polysaccharide of formula A, of the monosaccharide S is xylose; wherein the aqueous personal care rinse-off formulation comprises lt based on the weight of the aqueous personal care rinse-off formulation; 0.01% by weight of an alkyl sulfate surfactant and an alkyl ether sulfate surfactant.

This invention discloses an engineered methanogenic bacterium that produces high levels of squalene, its construction method, and its applications, belonging to the fields of metabolic engineering and synthetic biology. This is achieved by using a strong promoter in the host bacterium (methanogenic bacterium). P mxaF Expression of squalene synthase encoding gene sqs Overexpression of the gene encoding 1-deoxy-xylulose-5-phosphate synthase in the squalene synthesis pathway dxs1 and dxs2 Farnesyl pyrophosphate synthase encoding gene ispA Isopentenyl pyrophosphate isomerase encoding gene My friends Simultaneously overexpressing glucose-6-phosphate dehydrogenase zwf1 and the EMP pathway pfk1 and fba2 An engineered methanogenic bacterium producing squalene was obtained. Using this engineered methanogenic bacterium for squalene fermentation production can significantly increase squalene yield and has excellent prospects for industrial application.

The invention discloses xylose isomerase obtained based on an ancestor sequence construction method and application of the xylose isomerase. The xylose isomerase is obtained on the basis of an ancestor sequence construction method and has an amino acid sequence shown in SEQ ID NO.3, the capacity of converting xylose into xylulose can be endowed to yeast cells through independent expression or combined expression of the xylose isomerase, and then the capacity of converting xylose into other products is endowed to host cells. The invention also relates to an application of the xylose isomerase in producing chemicals such as ethanol and the like by using xylose as a substrate. When the xylose isomerase is expressed in yeast cells such as saccharomyces cerevisiae and the like, a host which does not have the capacity of converting xylose into xylulose originally can obtain the conversion capacity, and host cells are endowed with the capacity of producing chemicals such as ethanol by using xylose-rich raw materials such as xylose or lignocellulose hydrolysate and the like.

An L-rhamnose isomerase which can be obtained from a microorganism belonging to the genus Erwinia, has a subunit of a molecular mass of about 48 kDa as determined by SDS-PAGE, and has the substrate specificity of (A) and (B) described below. (A) has an isomerase activity which recognizes and reacts with CHO group at C1 and OH group at C2 of an aldose, converts CHO group at C1 into OH group, and converts OH group at C2 into CO group, or recognizes and reacts with OH group at C1 and CO group at C2 of a ketose, converts OH group at C1 into CHO group, and converts CO group at C2 into OH group. (B) has an activity of catalyzing isomerization between L-rhamnose and L-rhamnulose, between L-lyxose and L-xylulose, between L-mannose and L-fructose, between D-ribose and D-ribulose, between L-talose and L-tagatose, and between D-allose and D-psicose.

There is provided an aqueous personal care rinse-off formulation, the aqueous personal care rinse-off formulation comprising: a dermatologically acceptable aqueous vehicle; a dermatologically acceptable cleansing surfactant, wherein the dermatologically acceptable cleansing surfactant comprises an anionic surfactant; and an alkyl polysaccharide thickener; wherein the alkyl polysaccharide thickener comprises from 50% to 100% by weight, based on the weight of the alkyl polysaccharide thickener, of a linear alkyl polysaccharide of formula A, R-O-(S) nH (A) wherein R is a linear C9-15 alkyl group; wherein n is an average value from 1 to 2.5, and wherein S is a monosaccharide selected from the group consisting of ribulose, xylulose, ribose, arabinose, xylose, lyxose and mixtures thereof; and wherein 70% to 100% by weight, based on the weight of monosaccharide S in the linear alkyl polysaccharide of formula A, of the monosaccharide S is xylose.

This disclosure generally relates to the use of enzyme combinations or recombinant microbes comprising same to make isoprenoid precursors, isoprenoids and derivatives thereof including prenylated aromatic compounds. Novel metabolic pathways exploiting Claisen, aldol, and acyloin condensations are used instead of the natural mevalonate (MVA) pathway or 1-deoxy-d-xylulose 5-phosphate (DXP) pathways for generating isoprenoid precursors such as isopentenyl pyrophosphate (IPP), dimethylallyl pyrophosphate (DMAPP), and geranyl pyrophosphate (GPP). These pathways have the potential for better carbon and or energy efficiency than native pathways. Both decarboxylative and non-carboxylative condensations are utilized, enabling product synthesis from a number of different starting compounds. These condensation reactions serve as a platform for the synthesis of isoprenoid precursors when utilized in combination with a variety of metabolic pathways and enzymes for carbon rearrangement and the addition / removal of functional groups. Isoprenoid alcohols are key intermediary products for the production of isoprenoid precursors in these novel synthetic metabolic pathways. These precursors can be modified to various isoprenoid products through prenyl transferase, terpene synthase, or terpene cyclases. The production of prenylated aromatic compounds is achieved through prenyl transfer of the hydrocarbon units of isoprenoid precursors to polyketides.

The invention belongs to the technical field of biomedicine, and particularly relates to application of xylulose-5-phosphoric acid as an inflammatory bowel disease biomarker with intestinal fibrosis characteristics. It is found for the first time that xylulose-5-phosphoric acid is remarkably increased in a biological sample of a patient with the inflammatory bowel disease with the intestinal fibrosis characteristic, and the expression level of xylulose-5-phosphoric acid in the biological sample of the patient with the inflammatory bowel disease with the intestinal fibrosis characteristic is in a positive correlation relation with the occurrence degree of the intestinal fibrosis. The discovery provides an important therapeutic target for predicting or evaluating whether a subject suffers from the inflammatory bowel disease with the intestinal fibrosis characteristic by using the xylulose-5-phosphoric acid as the inflammatory bowel disease biomarker with the intestinal fibrosis characteristic.

The application provides use of L-xylulose as a diagnostic marker for children with Kawasaki disease of immunoglobulin G non-responsiveness, and application of L-xylulose as a diagnostic marker in preparation of a Kawasaki disease diagnosis product, the diagnostic marker being a marker in a sample of children with Kawasaki disease, and the Kawasaki disease diagnosis product including a product for predicting and / or evaluating treatment effect of Kawasaki disease. The application first proposes a diagnostic marker of children with Kawasaki disease of immunoglobulin G non-responsiveness of L-xylulose, and uses the diagnostic marker for predicting and / or evaluating treatment effect of Kawasaki disease, and has good stability and repeatability.

The present disclosure relates to D-xylulose 4-epimerase, mutants thereof, and uses thereof. Specifically, the present disclosure relates to a polypeptide having D-xylulose 4-epimerase activity, a method for preparing said polypeptide, and use of said polypeptide in the preparation of L-pentose using D-xylose or D-xylulose as a raw material. Compared with the traditional preparation method in the prior art, the new method for preparing L-pentose discovered in the present disclosure has simpler production process and reduces the cost of producing L-pentose.

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.

The present invention relates to a xylose isomerase derived from Antarctic krill and its mutants and applications, belonging to the field of enzymology, and the amino acid sequence of the xylose isomerase is shown in SEQ ID NO.1. The gene encoding the xylose isomerase is shown in SEQ ID NO.2. The present invention also provides a gene recombinant plasmid and a recombinant bacterium containing the xylose isomerase; the present invention also provides a xylose isomerase mutant, specifically EsXLI‑K253R and EsXLI‑D328A. The Antarctic krill xylose isomerase and its mutants obtained by the present invention can not only catalyze the isomerization of D‑xylose to generate D‑xylulose, but also have specificity for different substrates, and convert and produce many important raw materials and rare sugars in the pharmaceutical industry, and have very good application prospects. The xylose isomerase of the present invention has good adaptability to low temperatures and can be expressed in Escherichia coli cells.

The invention discloses a method for preparing L-arabinose, and belongs to the technical field of preparation of L-arabinose. The invention particularly relates to a method for preparing L-arabinose by utilizing in-vitro biotransformation, which comprises the following steps: converting 6-phosphogluconic acid into D-ribulose 5-phosphoric acid by adopting 6-phosphogluconic acid dehydrogenase; the method comprises the following steps: converting D-ribulose 5-phosphoric acid into D-xylulose 5-phosphoric acid by adopting D-ribulose 5-phosphoric acid 3-epimerase; the method comprises the following steps: converting D-xylulose 5-phosphoric acid into L-ribulose 5-phosphoric acid by adopting L-ribulose 5-phosphoric acid 4-epimerase; under the action of isomerase and dephosphorizing enzyme, the L-ribulose 5-phosphoric acid is converted into the L-arabinose. The method is a brand-new biological method for preparing the L-arabinose, the L-arabinose is obtained with higher yield and higher purity, the purification process is simple, the production cost of the L-arabinose can be reduced, and the preparation process is environment-friendly.

The invention discloses a construction method and application of yarrowia lipolytica engineering bacteria for high yield of itaconic acid, and the construction method comprises the following steps: step S1, by utilizing a CRISPR / Cas9 technology and combining a multi-copy insertion strategy, carrying out precise integration on a citrate lyase gene, a cis-aconitic acid synthetase gene and an itaconic acid synthetase gene, optimizing metabolic carbon flow and improving the yield of a target product; s2, constructing a dynamic regulation and control system, and regulating key gene expression by stages through an inductive promoter and a feedback regulation and control element to realize dynamic optimization of a metabolic pathway; s3, accurately positioning itaconic acid synthetase in mitochondria or peroxides through signal peptide, reducing generation of byproducts, enhancing DGA1 gene expression by utilizing a CRISPR activation technology, and improving the tolerance of the strain in a low-pH environment; and step S4, adding a xylose isomerase gene, a xylulose reductase gene and a fatty acyl-coenzyme A dehydrogenase gene, optimizing metabolic pathways of xylose and fatty acid, and realizing efficient conversion of multiple carbon sources.

The invention discloses xylose isomerase obtained based on an ancestor sequence construction method and application of the xylose isomerase. The xylose isomerase is obtained based on an ancestor sequence construction method and has an amino acid sequence as shown in SEQ ID NO.4, the capacity of converting xylose into xylulose can be endowed to yeast cells through independent expression or combined expression of the xylose isomerase, and then the capacity of converting xylose into other products is endowed to host cells. The invention also relates to an application of the xylose isomerase in producing chemicals such as ethanol and the like by using xylose as a substrate. When the xylose isomerase is expressed in yeast cells such as saccharomyces cerevisiae and the like, a host which does not have the capacity of converting xylose into xylulose originally can obtain the conversion capacity, and host cells are endowed with the capacity of producing chemicals such as ethanol by using xylose-rich raw materials such as xylose or lignocellulose hydrolysate and the like.

The invention provides a platycodon grandiflorum 1-deoxy-D-xylulose-5-phosphate reductoisomerase PgDXR1 gene, the nucleotide sequence of the platycodon grandiflorum 1-deoxy-D-xylulose-5-phosphate reductoisomerase PgDXR1 gene is as shown in SEQ ID NO. 1, and the amino acid sequence of a corresponding code is as shown in SEQ ID NO. 2. The invention further provides a plant overexpression vector containing the PgDXR1 gene and a genetically engineered host cell containing the PgDXR1 gene. In addition, the invention also provides an application of the PgDXR1 gene in regulation and control of synthesis of plant triterpenoid saponin. The invention provides the platycodon grandiflorum PgDXR1 gene related to synthesis of the triterpenoid saponin of the platycodon grandiflorum for the first time, and an expression product of the gene can positively regulate synthesis of the triterpenoid saponin; the invention provides new evidence for perfecting the synthetic route of the plant triterpenoid saponin, has important theoretical and practical significance for improving the quality of traditional Chinese medicinal materials, and provides a new way for regulating and controlling the content of the triterpenoid saponin of platycodon grandiflorum by utilizing genetic engineering.

The invention discloses xylose isomerase obtained based on an ancestor sequence construction method and application of the xylose isomerase. The xylose isomerase is obtained based on an ancestor sequence construction method and has an amino acid sequence as shown in SEQ ID NO.2, the capacity of converting xylose into xylulose can be endowed to yeast cells through independent expression or combined expression of the xylose isomerase, and then the capacity of converting xylose into other products is endowed to host cells. The invention also relates to an application of the xylose isomerase in producing chemicals such as ethanol and the like by using xylose as a substrate. When the xylose isomerase is expressed in yeast cells such as saccharomyces cerevisiae and the like, a host which does not have the capacity of converting xylose into xylulose originally can obtain the conversion capacity, and host cells are endowed with the capacity of producing chemicals such as ethanol by using xylose-rich raw materials such as xylose or lignocellulose hydrolysate and the like.

The invention discloses a high-yield alpha-farnesene aerobic methanophilic engineering bacterium as well as a construction method and application thereof, and belongs to the technical field of metabolic engineering and synthetic biology. The method comprises the following steps: expressing an alpha-farnesene synthase gene AFS by using a strong promoter PmxaF in host bacteria (aerobic methanophilic bacteria), overexpressing 1-deoxy-xylulose-5-phosphate synthase genes dxs1 and dxs2, a farnesyl pyrophosphate synthase gene ispA and an isopentenyl pyrophosphate isomerase gene Bsidi in a synthetic route of alpha-farnesene, and overexpressing 6-phosphate glucose dehydrogenase zwf1, the aerobic methanophilic engineering bacteria for producing the alpha-farnesene are obtained. When the methanophilic engineering bacterium is used for fermentation production, the yield of alpha-farnesene is obviously improved, and the methanophilic engineering bacterium has industrial application prospects.