93 results about "Xylose fermentation" patented technology

The invention discloses a recombinant yeast strain (Saccharomyces cerevisiae)) capable of efficiently metabolizing xylose, which is named SyBE005. The recombinant yeast strain has been collected in Common Microorganism Center of China Committee for Culture Collection of Microorganisms, the collection number is CGMCC No.6634, and the recombinant yeast strain has the capacity of efficiently metabolizing xylose to produce ethanol. The recombinant yeast strain SyBE005 can effectively ferment xylose to generate ethanol. The ethanol yield reaches 64% of the theoretical yield, and the yield of the byproduct xylitol is lower than 12%; and thus, the recombinant yeast strain can efficiently convert xylose into ethanol, and is an excellent strain utilizing cellulose hydrolysate.

The invention discloses a xylose fermentation strain resistant to inhibitors. The strain is named as SEB11 and has a preservation number of CGMCC No. 16570. The invention also relates to a construction method of the above-mentioned xylose fermentation strain, and the method comprises the steps of: selecting a starting strain SEB5; performing plasma mutagenesis treatment on the starting strain, andpicking out bacterial colonies which are better or similar to the starting strain in growth situation; and subjecting the picked strains to plate initial screening and actual saccharification liquidrescreening so as to obtain the xylose fermentation strain SEB11 resistant to inhibitors. The present invention also relates to applications of the above xylose fermentation strain in producing ethanol by using xylose in lignocellulose. The method adopts an industrial strain of the xylose as a starting strain, adopts a normal-pressure room-temperature plasma mutagenesis technique for mutagenesis,and obtains the xylose fermentation mutant strain SEB11 with excellent inhibitor tolerance according to the growth condition in a plate medium containing inhibitors and the actual saccharification liquid fermentation rescreening. The xylose consumption rate is significantly increased, and a better fermentation result exhibits.

The invention relates to an industrial saccharomyces cerevisiae strain capable of producing xylitol and a construction method of the industrial saccharomyces cerevisiae strain. The preservation number of the saccharomyces cerevisiae strain is CGMCC 11326. The construction method comprises the following steps: taking pK-XR-Ct plasmids as a template, taking delta-pB-F and delta-pB-R as primers, and carrying out PCR amplification to obtain DNA fragments A, taking the DNA fragments A as a template, and carrying out amplification to obtain DNA fragments B; screening the G418 optimal tolerance concentration of a saccharomyces cerevisiae fusion strain; converting the saccharomyces cerevisiae fusion strain; and screening unicellular converters to obtain the saccharomyces cerevisiae strain. The saccharomyces cerevisiae SEB6 strain prepared by the construction method provided by the invention has excellent performances of producing xylitol through xylose fermentation, and the yield of xylitol is high; and meanwhile, the problems that exogenous genes get lost and the expression level is low existing in the expression of the existing saccharomyces cerevisiae strains are avoided.

Xylose fermentation ethanol is one of the key technologies utilizing biomass to produce ethanol. A saccharomyces cerevisiae engineering bacterial strain is set up by a method of metabolic engineering. The bacterial strain not only can ferment the ethanol produced by the xylose, but also can automatically balance oxido-reduction cofactor, so as to be a metabolic engineering microzyme which has little by-product and can effectively use xylose fermentation for producing the ethanol. The conversion rate of xylose fermentation ethanol of bacterial strain reaches 88%, thus laying the foundation for utilizing the biomass to produce fuel ethanol.

The invention provides recombinant saccharomyces cerevisiae for producing ethanol by xylose fermentation and a construction method thereof. In the invention, candida boidinii is led to the saccharomyces cerevisiae to metabolize a DNA fragment of a coding gene of related enzymes of the xylose, so that the saccharomyces cerevisiae can secrete and express xylose isomerase the enzymatic reaction conditions of which are close to growth conditions of the saccharomyces cerevisiae, so the recombinant saccharomyces cerevisiae can effectively utilize the xylose to produce the ethanol, thus solving the technical problem that the saccharomyces cerevisiae can not utilize the xylose to produce the ethanol. The invention lays a foundation for industrial application of the saccharomyces cerevisiae for producing the ethanol by using xylose fermentation, thus having great economic benefit and social benefit.

The invention relates to a cell which comprises a nucleotide sequence encoding a xylose isomerase, wherein the amino acid sequence of the xylose isomerase has at least about 70% sequence identity to the amino acid sequence set out in SEQ ID NO: 3 and wherein the nucleotide sequence is heterologous to the host. A cell of the invention may be used in a process for producing a fermentation product, such as ethanol. Such a process may comprise fermenting a medium containing a source of xylose with a cell of the invention such that the cell ferments xylose to the fermentation product.

In view of problems in the existing cellulose ethanol preparation technologies that inhibitors in a cellulose hydrolyzate inhibit fermentation, xylose cannot be completely converted, glucose inhibitsfermentation of the xylose, and a cellulase acting temperature and a microbe fermentation temperature are non-uniform, the invention provides a fermentation method for producing xylitol and ethanol byusing undetoxified cellulose raw materials. The fermentation method comprises the steps of inoculum culture, xylose fermentation, cellulase adding, synchronous diastatic fermentation and the like. According to the method, simultaneous utilization of the xylose and the inhibitors is achieved by adopting an acetic acid and xylose co-utilization based Kluyveromyces marxianus strain, and thus, the problem in inhibitor removal is avoided; by adopting high-temperature synchronous diastatic fermentation, the problem that the cellulase is unmatched with a fermentation temperature is avoided; and compared with the existing cellulose ethanol fermentation technologies, the production cost can be remarkably reduced.

The invention discloses an Aureobasidium Pullulan producing pullulan with high yield by utilizing xylose and a production method of pullulan. The Aureobasidium Pullulan is taken as an original strain and subjected to ultraviolet mutagenesis to obtain a mutated strain which produces pullulan with high yield and secretes less pigment. The Aureobasidium Pullulan mutated strain AY82 is preserved in the China General Microbiological Culture Center with the data of Jan 18th, 2013 and the preservation number of CGMCC No.7154. The Aureobasidium Pullulan mutated strain AY82 can produce pullulan by utilizing fermentation of xylose, yield of pullulan is higher, after shake-flask culture is carried out on xylose fermentation culture medium for seven days, the yield of pullulan is 16.61g/L, and after culture by virtue of a 5L fermentation tank is carried out for seven days, the yield is 16.23g/L. Study on the Aureobasidium Pullulan producing pullulan by utilizing xylose can provide a new method for reasonably utilizing xylose, and additional value of xylose can be effectively enhanced.

The invention relates to a Saccharomyces cerevisiae strain for producing ethanol by quick fermentation of xylose and a construction method, discloses a Saccharomyces cerevisiae strain capable of producing ethanol by fermenting glucose, xylose and cellobiose at the same time, and solves the problem that existing Saccharomyces cerevisiae cannot be used for producing ethanol by using xylose and cellobiose. The Saccharomyces cerevisiae strain SEB3 is collected in China General Microbiological Culture Collection Center under CGMCC11323. The invention also provides a construction method of the Saccharomyces cerevisiae strain SEB3. The Saccharomyces cerevisiae strain has the advantages of high xylose fermenting capacity, high xylose consumption speed, high ethanol yield and the like; meanwhile, the Saccharomyces cerevisiae strain SEB3 is better in acid resistance and temperature tolerance, and both pH not lower than 3 and temperature not higher than 35 DEG C have no significant impact on the fermenting speed and efficiency of xylose and cellobiose.

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 relates to a method for removing salt in xylose fermentation liquor. By utilizing an ion exchange column series technology, impurity ions in solution are separated to obtain xylose liquor without salt. The method comprises the following specific execution steps: taking the pretreated xylose fermentation liquor as a raw material, quickly carrying out series connection after cation exchange columns are penetrated, realizing the saturated adsorption of cation exchange resin through the series connection of the cation exchange columns in sequence and obtaining qualified cation exchange solution; and taking the qualified cation exchange solution as a raw material, quickly carrying out series connection after anion exchange columns are penetrated, realizing the saturated adsorption of anion exchange resin through the series connection of the anion exchange columns in sequence and obtaining xylose liquor without salt.

The present invention relates to methods of reducing the toxicity of lignocellulosic hydrolysates which comprise one or more inhibitors. One method reduces the amount of furfural inhibitor leading to a more effective process. Another method reduces the amount of xylitol produced during the fermentation of xylose present in lignocellulosic hydrolysates. Naturally occurring aldo/keto reductase enzymes, as well as, enzymes produced by recombinant cells or by selective adaptation may be employed.

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.

The invention discloses a preparation method of cellulosic ethanol. The method includes the steps of firstly, performing explosion pretreatment on a cellulose raw material to obtain a preliminarily degraded material suitable for biomass conversion; secondly, mixing molasses with the material obtained in the first step, regulating pH to 3.5-4.5, and performing enzymolysis to obtain fermenting mash; regulating the pH of the fermenting mash obtained in the second step to 4-5, adding yeast which can use xylose fermentation to obtain ethanol to perform fermentation, adding Trichoderma reesei when the fermentation is performed for 6-10 hours, adding saccharomyces cerevisiae when the fermentation is performed for 10-16 hours, continuing fermenting for 30-48 hours to obtain a material containing the cellulosic ethanol, and separating ethanol from the material. The preparation method has the advantages that the ethanol is prepared by the effective resource utilization of the cellulose and the molasses, pentose utilization degree is increased, raw material use amount is lowered, and production cost and environment pollution can be lowered evidently.