47 results about "Xylose metabolism" patented technology

A strain of xylose-utilizing Zymomonas was engineered with a genetic modification to the glucose-fructose oxidoreductase gene resulting in reduced expression of GFOR enzyme activity. The engineered strain exhibits reduced production of xylitol, a detrimental by-product of xylose metabolism. It also consumes more xylose and produces more ethanol during mixed sugar fermentation under process-relevant conditions.

A strain of xylose-utilizing Zymomonas was engineered with a genetic modification to the glucose-fructose oxidoreductase gene resulting in reduced expression of GFOR enzyme activity. The engineered strain exhibits reduced production of xylitol, a detrimental by-product of xylose metabolism. It also consumes more xylose and produces more ethanol during mixed sugar fermentation under process-relevant conditions.

Production of ethanol using a strain of xylose-utilizing Zymomonas with a genetic modification of the glucose-fructose oxidoreductase gene was found to be improved due to greatly reduced production of xylitol, a detrimental by-product of xylose metabolism synthesized during fermentation.

Production of ethanol using a strain of xylose-utilizing Zymomonas with a genetic modification of the glucose-fructose oxidoreductase gene was found to be improved due to greatly reduced production of xylitol, a detrimental by-product of xylose metabolism synthesized during fermentation.

The invention belongs to the technical field of bioengineering, and particularly relates to a genetic engineering strain capable of effectively secreting D-psicose 3-epimerase and a construction method thereof. A D-psicose 3-epimerase gene rdpe from rumen bacterium Ruminococcus sp. 5_1_39B_FAA is obtained firstly, recombinant plasmid pMA5-RDPE construction and bacillus subtilis conversion are conducted, and then constitutive and secretive expression of RDPE in bacillus subtilis is achieved. By comparing three glucose-induced promoters, the optimal inducible promoter P[xylA] is obtained, and the RDPE secretion level is increased remarkably. By knocking out the xylose utilization gene xylAB (xylA and xylB), the xylose metabolism pathway of bacillus subtilis is blocked, the secretion amount of RDPE is further increased, and the optimal induced concentration of the inducer xylose is reduced to 0.5% from 4.0%. Finally, the engineered strain 1A751SD-XR is evaluated in a 7.5 L fermentation tank, and the RDPE secretion level can be as high as 95 U / mL and 2.6 g / L.

The invention discloses recombinant zymomonas mobilis capable of producing ethanol by using xylose and a fermentation method thereof. The recombinant zymomonas mobilis GX1 capable of producing the ethanol by using the xylose is preserved in China General Microbiological Culture Collection Center, and has a preservation number of CGMCC 3438. The controlling elements of Escherichia coli rrnB and related genes of xylose metabolism are fused to build plasmids with artificially fused operons for the first time; and recombinant zymomonas mobilis strains capable of producing the ethanol by using the xylose are obtained through a method of electrotransformation and acclimatization. The recombinant zymomonas mobilis can efficiently express exogenous genes, can efficiently produce the ethanol by using glucose and the xylose to ferment together at the temperature of between 30 and 34 DEG C, and can produce the ethanol by using corncob hydrolysate containing the xylose and the glucose. The strains have important significance for producing clean energy by effectively using waste lignocellulose and solving the current energy crisis.

The invention discloses a genetic engineering strain, a construction method and application thereof in xylitol production. The genetic engineering strain includes Escherichia coli and an expression vector transferred into the Escherichia coli. An XR gene is inserted to the downstream of the expression vector's promoter, the base sequence of the XR gene is shown as SEQ ID No.4, the promoter is Trc promoter, the 5' end of the XR gene has RBS from pET30a, and at least one of ptsG, xylA, xylB and ptsF genes in the Escherichia coli is inhibited or knocked out. Through translation initiation rate screening on xylose reductase gene and selection of appropriate RBS and promoter, the XR gene in the genetic engineering strain can obtain high efficiency expression at 30DEG C, and no inclusion body is generated. By knockout of the ptsG gene, the glucose effect is eliminated, and through knockout of the xylA, xylB and ptsF genes, xylose metabolism and xylitol phosphorylation are blocked.

Provided is a construction method of an escherichia coli genetically engineered bacteria producing succinic acid by xylose metabolism and the method for producing succinic acid by fermentation using the bacteria. The ATP biosynthesis pathway of escherichia coli is modified by means of molecular biology and the enzyme activity related to the pathway is over-expressed; thus the total ATP amount within escherichia coli cells is effectively increased such that the recombinant escherichia coli is able to grow using xylose metabolism, and the succinic acid synthesis efficiency is thereby significantly improved.

The invention belongs to the technical field of bioengineering, and relates to a genetic engineering bacterium for producing succinic acid and a method for producing the succinic acid by fermentation, in particular to a recombinant strain which is grown by utilizing xylose efficiently and is used for producing the succinic acid and a method for producing the succinic acid by utilizing the fermentation of the strain. The genetic engineering strain for producing the succinic acid belongs to the class of Escherichia coli BA204, and the conservation register number is CCTCC No:M2011207. A construction process comprises the steps of: inactivating or removing phosphoenolpyruvate carboxylase, and over-expressing phosphoenolpyruvate carboxylation kinase, so that the recombinant Escherichia coli can be grown by utilizing xylose metabolism to improve the synthetic efficiency of the succinic acid is improved substantially. In the fermentation method, a two-stage fermentation mode is adopted, wherein in an aerobic stage, biomass is improved; and in an anaerobic stage, acid is produced by the fermentation.

The invention provides a recombined saccharomyces cerevisiae strain for producing ethyl alcohol, a construction method of the recombined saccharomyces cerevisiae strain and a method for producing ethyl alcohol through the recombined saccharomyces cerevisiae strain. According to the recombined saccharomyces cerevisiae strain for producing ethyl alcohol, a wild type saccharomyces cerevisiae strain is used as an original strain, an XI xylose metabolism pathway is introduced into the original strain, the expression of four key genes in a PPP pathway is enhanced, meanwhile, the aldose reductase gene GRE3 is knocked out, the nitrobenzene phosphatase gene PHO13 is optionally knocked out, and XI protein and XK protein introduced exogenously are positioned to a yeast cell membrane through the membrane positioning effect of a membrane positioning group. The recombined saccharomyces cerevisiae strain for producing ethyl alcohol can efficiently carry out xylose metabolism, so that co-fermentation of C5 sugar and C6 sugar is achieved, and therefore the higher ethyl alcohol conversion rate is achieved.

The invention utilizes cloning and transformation techniques in combination with mutation and strain taming techniques to obtain yeasts having high xylose consumption rate and ethanol yield. The cloning and transformation used in the invention are to transform xylose metabolism genes to yeasts to solve the problem that some yeast strains cannot utilize xylose to produce ethanol. The mutation and strain taming used in the invention are to increase xylose consumption rate and ethanol yield to solve the problem of low rate and yield. By combining the above-mentioned technical means, the invention unexpectedly obtain a mutant having high xylose consumption rate and ethanol yield.

The invention relates to a method for the biotechnological production of xylitol, in which micro-organisms capable of metabolizing xylose to xylitol are used by modifying micro-organisms such that oxidation of NADH by enzymes other than the xylose reductase is reduced or excluded, cultivating the micro-organisms in a substrate containing xylose and 10-40 grams per liter of sulfite salt, and enriching the xylitol and recovering it from the substrate.

The invention discloses a building method of pediococcus acidilactici ZP26 for producing D-lactic acid by co-fermenting glucose and xylose, and belongs to the field of gene engineering. The method comprises the following building steps of integrating heterogenous xylose isomerase, xylulokinase, transketolase and transaldolase encoding genes onto pediococcus acidilactici ZP26 (with the preservationnumber being CGMCC NO.8665) genomes by using a thermosensitive knock-out system; knocking out phosphotransferase encoding genes so as to block the generation of byproducts of acetic acids; the capability of the engineering strain for co-fermenting glucose and xylose is obviously improved through an adaptive domestication strategy. The method provided by the invention has the advantages that the building of the xylose metabolism path is successfully realized for the first time; the engineering strain for producing optical pure D-lactic acid by co-fermenting glucose and xylose at high efficiency is obtained, is named as P.acidilactici ZY15, and has the preservation number of CGMCC NO.13612.

The invention discloses a wide host plasmid carrying xylose metabolism related genes and construction method thereof, belonging to the field of molecular biology techniques. The plasmid contains four xylose metabolism related enzyme genes, xylose isomerase (xylA), xylulokinase (xylB), transaldolase (talA) and transketolase (tktA), which are derived from E.coli DH5alpaha strain. The plasmid construction method uses the Gateway technology, to respectively design specific primers of four target genes xylA, xylB, talA and tktA, takes the E.coli DH5alpaha strain as the origin stain of the target genes to amplify the corresponding gene through the PCR; the PCR product performs BP recombination with the corresponding pDONR vector, and then the obtained Entry clones perform LR recombination with the pDEST14, to obtain the pDEST14-ABAT plasmid; the pDEST14-ABAT plasmid is connected to the Xha I single zyme cutting vector pBBR1MCS2 through the Xba I and Nhe I double zyme cutting product to obtained the recombinant plasmid pBBR1MCS2-ABAT. The superior strain shifted in the plasmid can greatly reduce production costs of cellulosic ethanol.

The invention provides saccharomyces cerevisiae of overexpression MIG1 genes and a preparing method and application of the saccharomyces cerevisiae. According to the saccharomyces cerevisiae, the genetic engineering technology is mainly used for shifting glycometabolism transcription factors into the industrial saccharomyces cerevisiae so as to prepare xylose metabolism engineering bacteria of the overexpression MIG1 genes; and the xylose metabolism engineering bacteria have the capacity of conducting fermentation in a pure xylose culture medium for generating ethyl alcohol, and therefore the yield of the ethyl alcohol in the process of producing fuel ethanol through glucose and xylose sugar mixture fermentation can be improved.

The invention belongs to the technical field of bioengineering, and particularly relates to a genetic engineering strain capable of effectively secreting D-psicose 3-epimerase and a construction method thereof. A D-psicose 3-epimerase gene rdpe from rumen bacterium Ruminococcus sp. 5_1_39B_FAA is obtained firstly, recombinant plasmid pMA5-RDPE construction and bacillus subtilis conversion are conducted, and then constitutive and secretive expression of RDPE in bacillus subtilis is achieved. By comparing three glucose-induced promoters, the optimal inducible promoter P[xylA] is obtained, and the RDPE secretion level is increased remarkably. By knocking out the xylose utilization gene xylAB (xylA and xylB), the xylose metabolism pathway of bacillus subtilis is blocked, the secretion amount of RDPE is further increased, and the optimal induced concentration of the inducer xylose is reduced to 0.5% from 4.0%. Finally, the engineered strain 1A751SD-XR is evaluated in a 7.5 L fermentation tank, and the RDPE secretion level can be as high as 95 U / mL and 2.6 g / L.

The invention uses Kluyveromyces marxianus yeast as a platform to construct a strain of knockout pyruvate decarboxylase and glycerol-3-phosphate dehydrogenase by means of genetic engineering, metabolic engineering, molecular biology and synthetic biology. The strain's growth is restored by metabolic regulation in order to improve the yield and production rate of pyruvate, and then the strain's xylose metabolism is improved, so that it has the ability to produce pyruvate with xylose. Eventually the glucose effect of the engineering strain is removed so that the engineered strain is capable of simultaneously saccharifying lignocellulose, using glucose and xylose and fermenting at high temperature to produce pyruvate. The Kluyveromyces marxianus strain YZB058 obtained by the present invention can produce pyruvate at the same time using glucose and xylose at 42 DEG C. At 42 DEG C, YZB058 is able to produce 29.21 g / l of pyruvate with 40.97 g / l of glucose and 20.37 g / l of xylose for 36 h, the production rate is at a rate of 0.81 g / l / h, and the total yield is at 0.48 g / g.

The invention relates to a genetic engineering strain for regulating expression activity of GRE3 genes in saccharomyces cerevisiae 1308-P. According to the invention, it discovers that the GRE3 genes in the saccharomyces cerevisiae can induce the generation of a by-product, namely xylitol, from xylose metabolism, and the generation of the xylitol is related to tolerance in a xylose fermenting process. It also discovers that the GRE3 genes, which are although negative regulator genes, cannot be completely knocked out. Experiments prove that the engineering strain, which is obtained by knocking out one of the GRE3 genes in the 1308-P, can improve the efficiency of fermenting ethanol by virtue of the xylose and reduce the generation of the by-product, namely the xylitol. Moreover, the modified bacterium also has the advantages that the original glucose utilization rate of an original strain, an inhibitor is high in tolerance and the like.

The invention discloses a method for promoting microbial cells to transport and / or hydrolyze xylo oligosaccharides and application thereof. Experiments prove that cello-oligosaccharide transport protein CDT-2 also has xylo-oligosaccharide transport capacity, beta xylosidase GH43-2 has hydrolysis effect on the xylo-oligosaccharides, according to the method, cdt-2 gene and / or gh43-2 gene are / is introduced into a microbial strain to obtain a recombinant microbial strain, and compared with a starting strain, the recombinant microbial strain acquires or improves the capability for transporting the xylo-oligosaccharides from extracellular to intracellular and / or hydrolyzing the xylo-oligosaccharides into xylose. By discovery of the xylo-oligosaccharide transport protein CDT-2 and application of the beta xylosidase GH43-2, an idea using modified yeast to directly use the xylo-oligosaccharides derived from hemicellulose degradation for producing biological chemicals is provided, co-fermentation of glucose, xylose, cello-oligosaccharide and xylo-oligosaccharide mixed sugar can be realized by co expression of cdt-2 and gh43-2 and cdt-1 and gh43-1 in brewer's yeast containing xylose metabolic pathway to produce the biological chemicals, and the production cost is greatly saved.

The invention provides a breeding method specific to lactobacillus capable of utilizing xylose. In the method, according to the characteristic that mesophilic lactobacillus with xylose metabolism capability can utilize the xylose but is not resistant to high temperature, the characteristic, of which utilizes the xylose, of the mesophilic lactobacillus is used as a genetic marker. Lactobacillus capable of tolerating high temperature but not utilizing the xylose is selected, and the high-temperature tolerance of the lactobacillus is utilized to serve as the genetic marker for the lactobacillus. Under an appropriate condition, protoplasts of two parents are prepared and fused. High temperature and the xylose are utilized as screening pressure so as to regenerate a fusant of the two parents under the appropriate condition, and thus, a fusant capable of utilizing the xylose and resisting certain high temperature is obtained finally. The fusant obtained by using the method can utilize 40g / l glucose and xylose at the temperature of 45 DEG C respectively, and the yield of the lactic acid can reach 25.14g / l and 20.96g / l.

The invention discloses a culture medium suitable for improvement of tolerance of glucose and xylose co-fermentation saccharomyces cerevisiae for multiple kinds of pretreatment inhibitors. The culturemedium takes a lignocellulose pretreatment solution containing multiple kinds of inhibitor components as a matrix, and yeast powder, peptone and xylose which are suitable for growth of xylose metabolism bacterial strains are added to the culture medium. The culture medium is suitable for improvement of tolerance of glucose and xylose co-fermentation saccharomyces cerevisiae for multiple kinds ofpretreatment inhibitors and beneficial to screening of glucose and xylose co-fermentation saccharomyces cerevisiae with improved tolerance for the pretreatment inhibitors. Compared with an existing screening culture medium only by adding one kind of inhibitor component, the culture medium has the advantage that the screening efficiency of high-tolerance saccharomyces cerevisiae can be greatly improved.

　In order to utilize xylose in yeast having a xylose-metabolizing capacity and reduce the concentration of acetic acid by metabolizing acetic acid in the medium during ethanol fermentation, this production method for ethanol comprises a step for performing ethanol fermentation by culturing, in a medium containing xylose, recombined yeast into which a xylose isomerase gene and an acetaldehyde dehydrogenase gene have been introduced.

The invention discloses a brewing yeast strain capable of metabolizing xylose. The strain is a brewing yeast (Saccharomyces cerevisiae) BSHH02B, and is preserved in the China General Microbiological Culture Collection Center (CGMCC) on Feb. 8th, 2012, wherein the preservation number is CGMCC No. 5747. The strain carries a unique xylose metabolizing way, i.e. a molecular xylose generates a molecular pyruvic acid and a molecular glycolaldehyde through two mesostate, i.e. xylonic acid and 3-deoxyl-D-glycerol-ketopentose acid. By the xylose metabolizing way, the brewing yeast BSHH02B can quickly grow by using the xylose under an aerobic condition, and can be applied to the production of chemical products by using xylose-containing raw materials, wherein the chemical products include ethanol, glycol, carboxylic acid and the like.

The invention relates to the field of biological preparation of ethanol, in particular to an industrial strain and a method for efficient xylose metabolism based ethanol production. The preservation number of the industrial strain is CGMCC No.15568. The gene expression clusters of an XR gene of xylose reductase, an XDH gene of xylitol dehydrogenase, an XK gene of xylulokinase, two copies of xylose transporter genes mgt05196, TAL1 and 2 copies of PYK1 genes are integrated into Saccharomyces cerevisiae by a constitutive strong promoter, and accordingly, glucose metabolism and xylose metabolismof Saccharomyces cerevisiae are improved, and ethanol production is increased.

The invention is intended to metabolize acetic acid and to lower acetic acid concentration in a medium at the time of xylose assimilation and ethanol fermentation by a yeast strain having xylose-metabolizing ability. To this end, a recombinant yeast strain having xylose-metabolizing ability and comprising an acetaldehyde dehydrogenase gene introduced thereinto is cultured in a medium containing cellulose, cellulase, and xylose to perform ethanol fermentation.

An acetic acid metabolizing ability of a recombinant yeast strain having xylose-metabolizing ability is to be improved. In such a recombinant yeast strain having xylose-metabolizing ability, the acetaldehyde dehydrogenase gene has been introduced and a gene encoding NADH dehydrogenase involved in reoxidation of cytoplasmic NADH on the mitochondrial outer membrane has been suppressed.

The present invention relates to a transformed microorganism capable of (a) a higher xylose isomerase activity than the equivalent microorganism prior to transformation; and / or (b) a higher growth rate in or on a growth medium comprising xylose than the equivalent microorganism prior to transformation; and / or (c) a faster metabolism of xylose than the equivalent microorganism prior to transformation; and / or (d) a higher production of ethanol when grown anaerobically on xylose as the carbon source than the equivalent microorganism prior to transformation.

Provided herein are non-naturally occurring microbial organisms having increased xylose metabolism and increased production of ethanol using xylose as a substrate, as well as methods to make and use these microbial organisms to produce ethanol.

The invention utilizes cloning and transformation techniques in combination with mutation and strain taming techniques to obtain yeasts having high xylose consumption rate and ethanol yield. The cloning and transformation used in the invention are to transform xylose metabolism genes to yeasts to solve the problem that some yeast strains cannot utilize xylose to produce ethanol. The mutation and strain taming used in the invention are to increase xylose consumption rate and ethanol yield to solve the problem of low rate and yield. By combining the above-mentioned technical means, the invention unexpectedly obtain a mutant having high xylose consumption rate and ethanol yield.