49 results about "Xylulokinase" patented technology

Strains of Zymomonas were engineered by introducing a chimeric xylose isomerase gene that contains a mutant promoter of the Z. mobilis glyceraldehyde-3-phosphate dehydrogenase gene. The promoter directs increased expression of xylose isomerase, and when the strain is in addition engineered for expression of xylulokinase, transaldolase and transketolase, improved utilization of xylose is obtained.

Described are recombinant yeast which ferment xylose to ethanol and which maintain their ability to do so when cultured for numerous generations in non-selective media. The preferred yeast contain multiple copies of integrated genes encoding xylose reductase, xylitol dehydrogenase, and xylulokinase fused to promoters which are non-glucose inhibited and which do not require xylose for induction. Also described are preferred methods for integrating multiple copies of exogenous DNA into host cells by transforming cells with replicative / integrative vectors, and then replicating the cells a number of times under selective pressure to promote retention of the vector in subsequent generations. The replicated vectors thus serve to integrate multiple copies of the exogenous DNA into the host cells throughout the replication / selection phase. Thereafter the selective pressure can be removed to promote loss of the vector in subsequent generations, leaving stable integrants of the exogenous DNA.

The present invention relates to a method for preparing an ethanol producing, xylose utilizing strain of Saccharomyces cerevisiae comprising genes for overexpression of xylose reductase, xylitol dehydrogenase and xylulokinase, wherein in addition to said genes for production o phosphoacetyltransferase, and acetaldehyde dehydrogenase are introduced and optionally overexpressed.

The present invention relates to a novel Saccharomyces cerevisiae strain utilizing xylose for fermenting ethanol expressing xylose isomerase (XI), overexpressing xylulokinase (XK), overexpressing the pentose phosphate pathway (PPP), and non-expressing aldose reductase (AR) and being adapted to growth in mineral defined medium with xylose as sole carbon source.

Recombinant Saccharomyces cerevisiae produced by transformation with heterologous polynucleotide sequences coding for xylulokinase (XKS) from Yersinia pestis and xylose isomerase (XI) are capable of xylose utilization. The transformants express these heterologous polynucleotides at a sufficient functional level to grow aerobically on xylose as the sole carbon source. Further transformation of the recombinant yeasts to overexpress one or more of the S cerevisiae genes PIP2, IMG2, MAK5, VPS9, COX10, ALE1, CDC7, and MMS4, permits the yeast to grow anaerobically on xylose as the sole carbon source. When grown under anaerobic conditions on a culture medium comprising both glucose and xylose, the transformed yeast exhibit increased ethanol productivity, with the yeast growing on the xylose to increase their biomass and fermenting the glucose to ethanol.

Genetic recombinant yeast expressing xylose reductase (XR), (wild-type or mutant) xylitol dehydrogenase (XDH), and xylulokinase (XK) and a method for highly efficiently producing ethanol from xylose using the yeast are provided. Pichia stipitis-derived XR and (wild-type or modified-type) XDH genes and Saccharomyces cerevisiae-derived XK gene were introduced via chromosomal integration. Thus, a genetic recombinant yeast having a high xylose fermentation rate, being capable of producing ethanol from xylose in high yields, and having high xylose fermentability in the presence of glucose, as well as a method using the recombinant yeast for highly efficiently producing ethanol from xylose or a saccharified solution from lignocellulose-based biomass are provided. Furthermore, a method for improving the xylose fermentability of the genetic recombinant yeast of the present invention via acclimatization treatment is also provided herein.

Disclosed are xylose-fermenting recombinant yeast strains expressing xylose reductase, xylitol dehydrogenase, and xylulokinase and having reduced expression of PHO13 or a PHO13 ortholog, as well as methods of fermenting xylose to obtain ethanol using the recombinant yeast strains.

Disclosed are xylose-fermenting recombinant yeast strains expressing xylose reductase, xylitol dehydrogenase, and xylulokinase and having reduced expression of PHO13 or a PHO13 ortholog, as well as methods of fermenting xylose to obtain ethanol using the recombinant yeast strains.

The invention discloses a method for improving the sugar utilization rate of clostridium acetobutylicum in fermentation of mixed sugar. The method comprises the following steps of: performing gene engineering modification on clostridium acetobutylicum, so that compared with wild type clostridium acetobutylicum, the clostridium acetobutylicum has the advantages that expression of g1cG gene can be inhibited, and the expression and activity of xylose transportprotein, xylose isomerase, and / or xylulokinase can be improved; and applying the obtained clostridium acetobutylicum which is subjected to gene engineering to fermentation of sugar. By the method, more xylose and arabinose can be used by clostridium acetobutylicum in the fermentation of the mixed sugar, a solvent product with high concentration can be produced, and the product yield can be improved; and the method has excellent industrial application prospect.

The invention discloses recombinant saccharomyces cerevisiae for producing dammarenediol and protopanoxadiol using xylose and a construction method. The construction method comprises the steps of replacing a promoter of a saccharomyces cerevisiae xylulokinase gene XKS1 with a promoter PFBA1 by virtue of a homologous recombination method, introducing xylose reductase XYL1 and a xylitol dehydrogenase XYL2 expression cassette, increasing the activities of transketolase TKL1 and transaldolase TAL1 so as to obtain recombinant bacteria 1, introducing a farnesyl-diphosphate farnesyltransferase gene ERG9, a squalene monooxygenase gene ERG1 and a dammarenediol synthase gene DS into the recombinant bacteria 1 so as to obtain recombinant bacteria 2, and introducing a nicotinamide adenine dinucleotide-hydroxymethylglutaryl coenzyme A reductase gene NADH-HMGr, farnesyl diphosphatesynthase ERG20 and a protopanoxadiol synthase-cytochrome P450 reductase fusion protein gene PPDS-ATR1 into the recombinant bacteria 2, so as to obtain recombinant bacteria 3. According to the recombinant saccharomyces cerevisiae, dammarenediol and protopanoxadiol can be artificially synthesized by virtue of xylose.

The present invention relates to a method for obtaining a recombinant yeast of Saccharomyces cerevisiae, which ferments lignocellulose raw materials to ethanol, including introducing DNA into a yeast so as to cause the yeast to have introduced genes encoding xylose reductase, xylitol dehydrogenase and xylulokinase.

Genetic recombinant yeast expressing xylose reductase (XR), (wild-type or mutant) xylitol dehydrogenase (XDH), and xylulokinase (XK) and a method for highly efficiently producing ethanol from xylose using the yeast are provided. Pichia stipitis-derived XR and (wild-type or modified-type) XDH genes and Saccharomyces cerevisiae-derived XK gene were introduced via chromosomal integration. Thus, a genetic recombinant yeast having a high xylose fermentation rate, being capable of producing ethanol from xylose in high yields, and having high xylose fermentability in the presence of glucose, as well as a method using the recombinant yeast for highly efficiently producing ethanol from xylose or a saccharified solution from lignocellulose-based biomass are provided. Furthermore, a method for improving the xylose fermentability of the genetic recombinant yeast of the present invention via acclimatization treatment is also provided herein.

The present invention relates to microorganisms of corynebacterium which can utilize xylose and to a method for producing L-lysine using same. More particularly, the present invention relates to microorganisms of corynebacterium which are modified, in which genes encoding xylose isomerase and xylulokinase which are xylose synthases are introduced to express the xylose synthase. The present invention also relates to a method for producing L-lysine, comprising a step of culturing the modified microorganisms of corynebacterium using xylose as a carbon source, and recovering L-lysine from the culture.

The invention discloses a strain for directly producing butanol by utilizing xylan as a sole carbon source. A classification name of the strain is Thermoanaerobacterium thermosaccharolyticum, and the number of the strain is M5; moreover, the strain is preserved in China Center for Type Culture Collection (CCTCC), the preservation date of the strain is 27th February, 2017, and the preservation number is CCTCC NO: M 2017072. The strain M5 can basically degrade 30g / L of xylan in 3-5 days and can be used as the sole carbon source for growth; after the xylan is degraded into xylose, pyruvic acid is obtained by xylose isomerase and xylulokinase; subsequently, acetic acid, ethanol, butyric acid and butanol are obtained through a series of metabolic pathways. According to the strain and the application of the strain disclosed by the invention, enzymes of all pathways can bear a high temperature of 55 to 65 DEG C, and the strain M5 is the one that can produce the butanol by directly utilizing the xylan, which is the only reported bacterial strain until now; therefore, a series of high-temperature resistant enzymes can be provided for industrial production of the butanol, and the strain has important application value.

The object is to develop a bacterium capable of fermenting glucose, mannose and xylose simultaneously, which can ferment a saccharified solution of a cellulose-type or lignocellulose-type biomass resource to produce ethanol, and to construct an energy-saving high-efficiency bioethanol conversion process. Thus, disclosed is Zymomonas mobilis bacterium which is prepared by integrating a gene encoding a phosphomannose isomerase derived from Escharichia coli into a levansucrase gene located on the chromosome by the double cross-over by means of a homologous recombsination method, and then introducing recombinant DNA prepared by binding a DNA fragment containing genes encoding a xylose isomerase, a xylulokinase, a transaldolase and a transketolase, respectively, all derived from Escherichia coli to a vector. Also disclosed is a method for producing ethanol by continuously fermenting a saccharified solution of a cellulose-type biomass resource in a system on which the Zymomonas mobilis bacterium is immobilized.

The invention discloses a Saccharomyces cerevisiae engineering bacterium for performing alcohol fermentation by using xylose, and a preparation method and application thereof. The strain contains the following nucleotide sequences: xylose reductase gene, xylitol dehydrogenase gene and xylulokinase gene; and the xylulokinase gene is overexpressed. The preparation method comprises the following steps: integrating a constitutive strong promoter to the upstream of the xylulokinase gene of the Saccharomyces cerevisiae initial strain genome by homologous recombination to obtain a xylulokinase-overexpressed strain; and transforming into Candida lusitaniae to obtain xylose reductase gene and xylitol dehydrogenase gene, thereby obtaining the Saccharomyces cerevisiae engineering bacterium for performing alcohol fermentation by using xylose. The Saccharomyces cerevisiae engineering bacterium can grow by using the xylose as the unique carbon source, and lays foundation for the subsequent construction of alcohol production by xylose / glucose co-fermentation. The engineering strain can be further screened and transformed to produce alcohol from lignocellulose, thereby greatly lowering the alcohol production cost.

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 provides a genetically engineered bacterium for producing malic acid efficiently by means of xylose fermentation and a construction method and application of the genetically engineered bacterium. In the recombinant bacterium, hosphopentose isomerase, L-fuculokinase, L-fucose-1-phosphate aldolase, aldehyde dehydrogenase, glycolate oxidase and malate synthase are overexpressed, and meanwhile xylulokinase, malate dehydrogenase and fumarate hydratase are knocked out, so that a malic acid synthesis route is obtained. According to the recombinant bacterium, the malic acid yield and the xylose conversion rate in shake flask culture and fermentation tank culture can reach ideal levels, and a good industrialized application prospect is achieved.

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 discloses a Saccharomyces cerevisiae engineering bacterium and its application in the production of ethanol. The invention provides Saccharomyces cerevisiae W32N55, and the preservation number of the Saccharomyces cerevisiae W32N55 is CGMCC NO.6090. The invention also provides an application of the Saccharomyces cerevisiae W32N55 in the preparation of ethanol. Experiments of the invention prove that the engineering bacterium W32N55 provided in the invention is obtained through obtaining the Saccharomyces cerevisiae engineering bacterium by the introducing xylose reductase gene (XYL1) and xylitol dehydrogenase gene (XYL2) to an original strain and by improving the activity of xylulokinase (XK), and through allowing the engineering bacterium containing the XYL1, the XYL2 and XK gene to undergo adaptive acclimation.

The present disclosure relates to host cells containing a recombinant xylose reductase, a recombinant cellodextrin transporter, a recombinant intracellular β-glucosidase, and lacking xylitol dehydrogenase and xylulokinase, and to methods of using such cells for producing xylitol from cellulosic biomass containing cellodextrin and xylose.

A xylose isomerase (XI) enzyme which exhibits increased activity and affinity for xylose is produced by strain TC2-24 of the rumen bacterium, Prevotella ruminicola. The gene encoding this enzyme may be used to produce improved recombinant yeast capable of utilizing xylose. The recombinant yeast are preferably transformed with heterologous polynucleotide sequences coding both the P. ruminicola XI, and the xylulokinase (XKS) of a Prevotella species. Yeast transformed with the polynucleotide sequences coding both of these XI and XKS exhibit significantly increased xylose utilization and cell growth on a culture medium containing xylose as the sole carbon source, in comparison to yeast transformed with XKS and XI from other sources.

A method for producing a strain of Saccharomyces cerevisiae with introduced genes coding for xylose reductase, xylitol dehydrogenase and xylulokinase and with improved ethanol production, improved xylose conversion, reduced xylitol production and improved inhibitor tolerance is described. The method comprises culturing a strain of Saccharomyces cerevisiae at a continuous mode with a medium comprising essentially only xylose as carbon source at a temperature of 25-38° C., preferably 30-35° C., and an airflow of 0.040-0.055 vvm, and increasing the dilution rate to maintain a constant cell level, said cell level being in the range of 1.5-3.0 determined by optical density or equivalent analytical means, and adding at least one inhibitor to the cells and gradually increasing the addition of said inhibitor. Further, strains of Saccharomyces cerevisiae obtained by the method according to the invention are described.

Recombinant Saccharomyces cerevisiae produced by transformation with heterologous polynucleotide sequences coding for xylulokinase (XKS) from Yersinia pestis and xylose isomerase (XI) are capable of xylose utilization. The transformants express these heterologous polynucleotides at a sufficient functional level to grow aerobically on xylose as the sole carbon source. Further transformation of the recombinant yeasts to overexpress one or more of the S cerevisiae genes PIP2, IMG2, MAK5, VPS9, COX10, ALE1, CDC7, and MMS4, permits the yeast to grow anaerobically on xylose as the sole carbon source. When grown under anaerobic conditions on a culture medium comprising both glucose and xylose, the transformed yeast exhibit increased ethanol productivity, with the yeast growing on the xylose to increase their biomass and fermenting the glucose to ethanol.

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.

Disclosed herein is a newly discovered problem and solution for engineering S. cerevisiae to ferment xylose to make ethanol utilizing xylose isomerase to convert xylose to xylulose for entry, via xylulokinase, into the pentose phosphate pathway. The problem is that when grown on a media containing xylose xylitol tends to accumulate in the cell despite the absence of xylose reductase activity in S. cerevisiae. Xylitol inhibits the activity of xylose isomerases. One solution described is to simultaneously express an exogenous xylitol dehydrogenase along with the exogenous xylose isomerase while optionally also overexpressing xylulokinase in the absence of expression of a xylose reductase. Another solution is a xylose isomerase from Bacteroides fragilis which is less inhibited by xylitol than other xylose isomerases, exemplified by E. coli xylose isomerase. Expression of the Bacteroides fragilis xylose isomerase may be used alone, or in combination with expression of a xylitol dehydrogenase and optionally over expression of xylulokinase to improve ethanol production from xylose.

Disclosed herein is a newly discovered problem and solution for engineering S. cerevisiae to ferment xylose to make ethanol utilizing xylose isomerase to convert xylose to xylulose for entry, via xylulokinase, into the pentose phosphate pathway. When grown on a media containing xylose xylitol tends to accumulate in the cell despite the absence of xylose reductase activity in S. cerevisiae. Xylitol inhibits the activity of xylose isomerases. One solution described is to simultaneously express an exogenous xylitol dehydrogenase along with the exogenous xylose isomerase while optionally also overexpressing xylulokinase in the absence of expression of a xylose reductase. Another solution is a xylose isomerase from Bacteroides fragilis which is less inhibited by xylitol than other xylose isomerases, exemplified by E. coli xylose isomerase. Expression of the Bacteroides fragilis xylose isomerase may be used alone, or in combination with expression of axylitol dehydrogenase and optionally over expression of xylulokinase to improve ethanol production from xylose.