353results about "Racemaces/epimerases" patented technology

The present invention provides methods for generating CMP-sialic acid in a non-human host which lacks endogenous CMP-Sialic by providing the host with enzymes involved in CMP-sialic acid synthesis from a bacterial, mammalian or hybrid CMP-sialic acid biosynthetic pathway. Novel fungal hosts expressing a CMP-sialic acid biosynthetic pathway for the production of sialylated glycoproteins are also provided.

The invention relates to newly discovered nucleic acid molecules and proteins associated with prostate cancer including pre-malignant conditions. Compositions, kits, and methods for detecting, characterizing, preventing, and treating human prostate cancers are provided.

The present invention relates to eukaryotic cells which have the ability to convert L-arabinose into D-xylulose 5-phosphate. The cells have acquired this ability by transformation with nucleotide sequences coding for an arabinose isomerase, a ribulokinase, and a ribulose-5-P-4-epimerase from a bacterium that belongs to a Clavibacter, Arthrobacter or Gramella genus. The cell preferably is a yeast or a filamentous fungus, more preferably a yeast is capable of anaerobic alcoholic fermentation. The may further comprise one or more genetic modifications that increase the flux of the pentose phosphate pathway, reduce unspecific aldose reductase activity, confer to the cell the ability to directly isomerise xylose into xylulose, increase the specific xylulose kinase activity, increase transport of at least one of xylose and arabinose into the host cell, decrease sensitivity to catabolite repression, increase tolerance to ethanol, osmolarity or organic acids; and/or reduce production of by-products. The cell preferably is a cell that has the ability to produce a fermentation product such as ethanol, lactic acid, 3-hydroxy-propionic acid, acrylic acid, acetic acid, succinic acid, citric acid, amino acids, 1,3-propane-diol, ethylene, glycerol, -lactam antibiotics and cephalosporins. The invention further relates to processes for producing these fermentation products wherein a cell of the invention is used to ferment arabinose into the fermentation products.

The invention discloses genetically engineered bacteria capable of increasing the yield of lactoyl-N-trisaccharide II and a production method, and belongs to the field of microbial genetic engineering. According to the invention, the expression of glmM, glmU, glmS and lgtA in a lactoyl-N-trisaccharide II synthetic pathway is regulated and controlled in a combined manner, so the carbon flux of a metabolic pathway is accurately regulated and controlled, and the metabolic pressure is relieved; the expression of wecB, nagB and lacZ in an escherichia coli host, namely the lactoyl-N-trisaccharide IIsynthetic pathway is knocked out, so the yield of the lactoyl-N-trisaccharide II is further increased; in a flask shaking experiment, the capacity of escherichia coli for producing the lactoyl-N-trisaccharide II is increased to 4.82 g/L from 0.53 g/L; in a fermentation tank with a volume of 3 L, the yield of the lactoyl-N-trisaccharide II reaches 46.2 g/L; and thus, thegenetically engineered bacteria have industrial application prospect.

The invention discloses a method for efficiently preparing D-psicose 3-epimerase and a use of the D-psicose 3-epimerase and provides a method for efficiently preparing an enzyme catalyst for catalyzing the same reaction through isozyme combined expression. The method utilizes corynebacterium glutamicum as a host cell to construct a recombinant strain expressed by plasmid dissociation and chromosomal integration, measures D-fructose catalytic efficiency, improves enzyme catalytic efficiency by 2-4 times than that of single expression of D-psicose 3-epimerase through combined expression and hasa conversion ratio of 29% when 70% of fructose is a substrate. The method improves D-psicose production efficiency and is suitable for industrial production of D-psicose. The invention also disclosesa novel use of the D-psicose 3-epimerase in psicose synthesis. The enzyme is derived from Paenibacillus senegalensis, has catalytic activity of about 25 U/mg and can be used to convert D-fructose intoD-psicose.

The invention discloses constructed recombinant escherichia coli and a method for biosynthesis of 3'-sialyllactose. The recombinant escherichia coli is named as E.coli-XYY which has a synthesis pathway of the 3'-sialyllactose. Meanwhile, the invention also discloses a constructing method. At the same time, the invention solves the problems of the prior art and provides an efficient gene knockout scheme; an original strain, after undergoing genetic engineering transformation, can produce the 3'-sialyllactose only, without changing other properties of the strain, so that influence on fermentation production is avoided; since mature escherichia coli plasmid is adopted by the strain, bacterium growth and normal metabolism do not affected in a metabolic process. The recombinant escherichia coli constructed by the invention has a good application prospect; therefore, a new thought is provided for the production of the 3'-sialyllactose by virtue of a biological method.

The invention provides a D-psicose-3-epimerase mutant with improved catalytic activity and an application of the mutant and particularly provides mutational D-psicose-3-epimerase. The mutational D-psicose-3-epimerase is obtained by mutation in at least three loci selected from the following groups: the 73rd aspartic acid (D), the 111st tyrosine (Y), the 188th asparaginate (N) and the 250th glycine(G) of wild D-psicose-3-epimerase corresponding to SEQ ID NO:1. The mutational D-psicose-3-epimerase has very high catalytic activity and catalytic efficiency (reaching up to 29.6%).

The invention relates to a preparation method of high-purity D-psicose. The method comprises the following steps: (a) preparing a D-psicose epimerase crude enzyme preparation; (b) immobilizing the crude enzyme preparation prepared in the step (a) and glucose isomerase; (c) preparing a mixed solution containing D-psicose, fructose and glucose; (d) decolorizing, filtering and hybridizing the mixed solution prepared in the step (c) to obtain a D-psicose solution and a mixed solution of the fructose and the glucose; (e) performing chromatographic separation, concentration, crystallization or drying on the D-psicose solution prepared in the step (d) to obtain D-psicose.

The endogenous pnp gene encoding polynucleotide phosphorylase in the Zymomonas genome was identified as a target for modification to provide improved xylose utilizing cells for ethanol production. The cells are in addition genetically modified to have increased expression of ribose-5-phosphate isomerase (RPI) activity, as compared to cells without this genetic modification, and are not limited in xylose isomerase activity in the absence of the pnp modification.

The invention discloses a D-psicose 3-epimerase mutant with improved catalytic efficiency and belongs to the technical field of enzyme engineering. The Dorea sp. DPEase mutant enzyme A38E/G105A keepsthe optimal catalytic conditions. Under the optimal catalytic conditions, the relative enzyme activity of the enzyme for catalytic conversion of D-fructose as a substrate into D-psicose is improved by38.6%. The discovery has an important research value for the industrial production of D-psicose.

The invention relates to recombinant cells and their use in the production of ethylene glycol.

The invention discloses a D-psicose 3-epimerase production strain and an immobilization method thereof, and belongs to the technical field of bioengineering. According to the invention, recombinant bacillus subtilis pHY300PLK-DPEase for producing D-psicose 3-epimerase is constructed, and the recombinant bacterium (the recombinant bacillus subtilis) serves as the production strain; an enzyme activity recovery rate of immobilized cells reaches 64%, the optimum temperature of the immobilized cells is improved by 5 DEG C in comparison with that of whole cells and the optimum pH value of the immobilized cells is free from obvious change; and after continuous conversion with 300g/L of fructose as a substrate for seven times, a conversion rate can be still kept at 28% and residual enzyme activitycan be still kept at 81%. The immobilization method is simple and easy to implement and immobilized particles are excellent in performance; therefore, a quite high industrial application value is achieved.

The invention discloses a construction method of an engineering strain for generating allulose and an application thereof. The construction method comprises the following steps: increasing content ofintracellular fructose 6-phosphoric acid by reducing enzymatic activity of fructose 6-phosphokinase and glucose 6-phosphate dehydrogenase in corynebacterium glutamicum and enhancing enzymatic activityof glucokinase and glucose 6-phophate isomerase by regulating glucose intracellular metabolism; constructing a synthetic route of allulose composed of 6-aloxone phosphate 3-epimerase and 6-aloxone phosphate phosphorylase; constructing a metabolic pathway of fructose composed of fructose transmittase and fructokinase; constructing a metabolic pathway of glycerinum composed of glycerol transmittase, glycerol dehydrogenase and dihydroxyacetone kinase, thereby acquiring a corynebacterium glutamicum recombinant strain. The strain is capable of metabolizing glycerinum, glucose, fructose or saccharose for synthesizing allulose. Compared with the present reported method for compounding allulose through bioconversion of fructose, the construction method provided by the invention has the advantagesof high conversion rate, low production cost, and the like, and is suitable for large-scale production of allulose.

The invention belongs to the technical field of genetic engineering and in particular relates to novel D-allulose 3-epimerase, DNA (Deoxyribonucleic Acid) for encoding the novel D-allulose 3-epimerase, an expression vector and a transformant containing the DNA and application of the enzyme to production of D-allulose. The D-allulose 3-epimerase is derived from thermoacidophile mesoaciditoga lauensis of a deep-sea spring and has relatively high conversion rate and thermal stability when being used for converting D-fructose into the D-allulose.

The present invention provides a novel psicose epimerase derived from Flavonifractor plautii and capable of converting fructose to psicose. The novel psicose epimerase according to the present invention possesses an activity producing psicose by epimerizing the carbon-3 position of fructose, and has maximal activity for the conversion of fructose to psicose at a relatively high temperature and a pH less than or equal to neutral, has excellent thermal stability, and can mass-produce psicose from fructose in a high yield for a short amount of time. Therefore, the psicose epimerase according to the present invention is advantageous in the industrial production of psicose, and it is expected that the psicose produced thereby can be usefully utilized in the functional sugar industry and also as materials for health food, medicine, cosmetics, and the like using the psicose.

The invention relates to a method for efficiently expressing preparation of UDP-glucose-4-epimerase. The method comprises the steps that a recombinant expression vector is constructed by using a UDP-glucose-4-epimerase (GalE) gene and a carrier of bacillus subtilis; the recombinant expression vector is then transformed into the bacillus subtilis to construct recombinant engineered bacteria; and the recombinant engineering bacteria are induced to culture in a liquid medium, bacterial liquid is centrifuged, and liquid supernatant is taken. The method has a high yield of the UDP-glucose-4-epimerase, relatively pure proteins, easy recovery and purification and simple production operation, and provides convenience for industrial large-scale production of GalE, output is improved, time and laborare saved, and the cost is saved. In particular, security assurance is provided for the application of the UDP-glucose-4-epimerase in the food industry, and great significance is achieved.

The invention discloses bacillus subtilis genetically-engineered bacteria for producing tagatose and a method for preparing the tagatose. The genetically-engineered bacteria are used for constructingheat-resistant alpha-glucan phosphorylase, heat-resistant phosphoglucomutase, heat-resistant glucose phosphate isomerase, heat-resistant 6-tagatose phosphate epimerase and heat-resistant 6-tagatose phosphate phosphatase which are independently expressed or co-expressed. By utilizing the genetically-engineered bacteria, starch can be effectively converted into the tagatose. Compared with the existing method for producing the tagatose, the method disclosed by the invention has the advantages of suitability for whole-cell recycling, high safety, high yield, simple production process, low cost, easiness in large-scale preparation and the like.

The invention provides a mutant of D-allulose 3-epimerase. The amino acid sequence of the mutant is an amino acid sequence obtained through replacing the 124th asparagine with arginine and replacing the 63rd serine with glycine on the base of the amino acid sequence of the D-allulose 3-epimerase as shown in SEQID NO:1, or is an amino acid sequence obtained by replacing the 105th valine with alanine, replacing 124th asparagine with arginine and replacing the 63rd serine with glycine. The catalytic activity of the mutant disclosed by the invention is notably improved, and is 179% or 223% of thatof a wild type mutant; besides, the temperature stability is also notably improved, and the half-life of the mutant at 60 DEG C is 1.7 times or 3.7 times of that of the wild type mutant. The mutant has important significance in production of the D-allulose under the high-temperature condition.