61 results about "Arabinose isomerase" patented technology

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 present invention relates to a method for producing a L-arabinose utilizing yeast strain for the production of ethanol, whereby a yeast strain is modified by introducing and expressing araA gene (L-arabinose isomerase), araB gene (L-ribulokinase D¹²¹-N) and araD gene (L-ribulose-5-P 4-epimerase) and carrying additional mutations in its genome or overexpressing a TAL1 (transaldolase) gene, enabling it to consume L-arabinose, to use it as the only carbon source, and to produce ethanol, as well as a method for producing ethanol using such a modified strain.

Recombinant microorganisms are useful for producing xylitol by fermentation of arabinose. The recombinant microorganisms are produced by transformation of host microorganisms with heterologous polynucleotide sequences coding for each of L-xylulose reductase, D-tagatose 3-epimerase, and L-arabinose isomerase, which transformants express the heterologous polynucleotides at a sufficient functional level to be effective to produce xylitol from arabinose. Production of xylitol is effected by contacting these recombinant microorganisms with a substrate comprising arabinose under conditions effective to produce xylitol from arabinose.

The present invention relates to a thermophilic arabinose isomerase and a method of manufacturing tagatose using the same, and more precisely, a gene encoding arabinose isomerase originating from the thermophilic Thermotoga neapolitana DSM 5068, a recombinant expression vector containing the gene, a method of preparing a food grade thermophilic arabinose isomerase from the recombinant GRAS (Generally Recognized As Safe) strain transformed with the said expression vector, and a method of preparing tagatose from galactose using the said enzyme.

The present invention relates to a recombinant GRAS (Generally Recognized As Safe) strains expressing thermophilic arabinose isomerase as an active form and method of food grade tagatose by using the same, and more precisely, a gene encoding arabinose isomerase originating from the thermophilic Geobacillus stearothermophilus DSM22 and Geobacillus thermodenitrificans, a recombinant expression vector containing the gene, a recombinant GRAS strains expressing the thermophilic arabinose isomerase as an active form by transformed with the expression vector, and a method of preparing food grade tagatose from galactose by using the same.

The invention discloses a gene engineering bacterium for coexpressing L-arabinose isomerase gene and mannitose-6-phosphoric acid isomerase. The strain comprises nucleotide sequences disclosed as SEQ ID NO:1 and SEQ ID NO:2. The gene engineering bacterium can be used for producing L-ribose by catalyzing L-arabinose, and has the advantages of one-step conversion, simple technique and high conversion rate; by using the gene engineering bacterium, the conversion rate of L-ribose is up to 25-50%; and thus, the gene engineering bacterium has favorable industrialization prospects.

The invention discloses a recombinant L-arabinose isomerase (L-AI) as well as a gene and preparation method thereof and a method for preparing D-tagatose by utilizing the L-AI. Especially bacillus subtilis is used for expressing L-arabinose isomerase, the recombinant L-arabinose isomerase with biological activity is obtained, and the L-AI is more beneficial to industrial production of D-tagatose. The preparation method disclosed by the invention has the characteristic of simplicity, high efficiency and short cycle.

The invention discloses L-AI (L-arabinose isomerase). The L-AI is prepared through the step as follows: 279th phenylalanine of L-AI of Bacillus coagulans NL01 is mutated into isoleucine, and the L-AI is obtained, wherein the GenBank registration number of a nucleotide sequence of an L-AI gene araA is KX356659. The invention further discloses escherichia coli containing the L-AI as well as a construction method and an application of the escherichia coli. According to the constructed recombinant escherichia coli, F279I expressed by the escherichia coli has high catalytic efficiency on D-galactose. The optimal reaction temperature of a whole-cell catalysis reaction system is mild, a browning reaction can be avoided, and the L-AI better facilitates industrial production of D-tagatose when compared with wild type L-AI and other common L-AI from thermophilic bacteria and thermoacidophiles. Meanwhile, the whole-cell catalysis reaction system adopts simple components and has greater industrial production and application potential and economic value.

The invention discloses a method for preparing D-tagatose by an enzyme process. The method comprises the following steps: 1) separately establishing engineering bacteria containing galactitol dehydrogenase gene and engineering bacteria containing NADH oxidase gene or establishing coexpression engineering bacteria containing galactitol dehydrogenase gene and NADH oxidase gene; 2) fermenting the established engineering bacteria to obtain a whole cell containing galactitol dehydrogenase and NADH oxidase; and 3) with the whole cell containing galactitol dehydrogenase and NADH oxidase or the free enzyme of galactitol dehydrogenase and NADH oxidase as a catalyst, catalyzing the galactitol by taking NAD+ as a hydrogen acceptor in a weakly alkaline condition to obtain D-tagatose. Compared with traditional production method depending on L-arabinose isomerase, in the invention, the substrate conversion rate is high (>99.0%) and the product is easy to separate; and moreover, the co-product of a coenzyme circulation system adopted in the method is water which does not influence the separation and purification of the principal product.

The invention belongs to the technical field of bioengineering and specifically relates to a method for biosynthesis of D-tagatose by an immobilized enzyme catalyst. The method for biosynthesis of theD-tagatose by the immobilized enzyme catalyst is as follows: first, recombinant Bacillus subtilis is prepared, and an L-arabinose isomerase immobilized enzyme catalyst is constructed; and recombinantBacillus subtilis spores are added to a D-galactose reaction solution for transformation by oscillation under certain conditions to obtain the D-tagatose. The novel food-safe immobilized enzyme catalyst is constructed, the biotransformation process for biosynthesis of the D-tagatose by the immobilized enzyme catalyst is optimized, the transformation rate is improved, the specific activity of theimmobilized enzyme catalyst is as high as 2.10* 10<-9> U/spore, and the transformation rate of the D-tagatose reaches 95%. A new green, safe, high-efficiency and economical D-tagatose synthesis technology and method are developed, the high-efficiency production of the food-grade D-tagatose is realized, and the method has broad industrial application prospects.

The invention belongs to the field of biology and chemical industry, and particularly discloses a method for continuously producing D-tagatose by adopting D-galactose as a raw material on the basis of enzymatic isomerization reaction and a continuous chromatographic separation in-situ coupling technology. The method comprises the following steps of preparing a buffering solution; adequately dissolving the thermophilic L-arabinose isomerase in the water to obtain an enzyme solution; adequately dissolving D-galactose in the water to obtain a raw material solution; mixing and preheating the raw material solution, the buffering solution and the enzyme solution to obtain a feeding solution of a simulated moving bed reactor (SMBR); and placing the feeding solution into the SMBR to obtain a D-tagatose product solution through the in-situ reaction and separation. By determining the appropriate operating condition of the SMBR, the conversion rate of the D-galactose reaches more than 80 percent, the purity of the D-tagatose reaches more than 95 percent, and the yield is more than 80 percent. The method is low in cost, less in pollution and high in conversion rate; moreover, continuity in production can be realized, the consistency of the product quality can be guaranteed, and the commercialized application prospect is good.

The invention discloses a method for producing recombinant mixed L-arabinose isomerase and belongs to the field of biological technology. The method comprises the steps of: first, cloning L-arabinose isomerase genes of bacillus stearothermophilus, thermotoga neapolitana and escherichia coli; constructing a pichia pastoris expression vector containing expression frameworks of the three L-arabinose isomerase genes and converting the vector into pichia pastoris to obtain engineering bacteria; and fermenting the pichia pastoris engineering bacteria to produce the recombinant mixed L-arabinose isomerase. The recombinant mixed enzyme has much higher enzymatic activity than a single enzyme with pichia pastoris as an expression vector, and has high enzymatic activity for isomerizing D-galactose into D-tagatose at a pH of 6.0 and at a temperature of 80 DEG C, which meet the production condition of isomerizing D-galactose into D-tagatose. The method provided by the invention is conducive to the solution of the problem that development of the industry of producing D-tagatose by an enzymic method is constrained as there is no L-arabinose isomerase that meets the requirements of an optimum pH of 5.0-6.0 and an optimum temperature of above 45 DEG C to produce bacterial strains, and thus helps promote the industry of producing D-tagatose by an enzymic method.

The invention provides a recombinant L-arabinose isomerase LPAI and a construction method and application thereof. The recombinant L-arabinose isomerase LPAI is constructed by utilizing a genetic engineering means; and the recombinant L-arabinose isomerase LPAI can be applied to preparation of D-tagatose by taking D-galactose as a substrate, and the problems of low conversion efficiency, high cost and the like in a D-tagatose production process are effectively solved.

The invention discloses L-arabinose isomerase and application thereof in production of L-ribulose. The invention further discloses a gene sequence SEQ ID NO:1 for coding the L-arabinose isomerase, a genetically engineered bacterium containing the L-arabinose isomerase and a construction method thereof and application of the L-arabinose isomerase and the genetically engineered bacterium thereof in production of the L-ribulose. The L-arabinose isomerase has higher catalytic efficiency on L-arabinose on the condition that the temperature ranges from 20 DEG C to 70 DEG C and the pH ranges from 5.0 to 10.0, and the activity and the thermal stability of the L-arabinose isomerase can be greatly promoted in the presence of low-concentration irons such as Mn<2+> and Co<2+>. Under the optimal catalytic conditions, by means of the L-arabinose isomerase, the conversion rate of the L-arabinose can reach 95 percent or above, and the L-arabinose isomerase has very important significance and economic value to biological production of the L-ribulose.

The invention discloses a method for regulating and expressing L-arabinose isomerase by using Pichia methanolica pGAP, belonging to the field of biotechnology. The method comprises the following steps of: amplifying a pGAP promoter in Pichia methanolica; consturcting a Pichia methanolica expression vector of an L-arabinose isomerase gene regulated by the pGAP and converting the vector into a Pichia methanolica genome; screening a high-copy recombinant as an engineering bacterial strain according to a resistance gene carried on the vector; inoculating the engineering bacterial strain into a liquid nutrient medium containing a carbon source, fermenting engineering bacteria and carrying out secretory expression to obtain the L-arabinose isomerase. The invention has low production cost and short fermentation cycle; and the L-arabinose isomerase regulated and expressed by utilizing the Pichia methanolica pGAP is beneficial to the purification of the product, solves the problems that the L-arabinose isomerase produced by utilizing bacterial strains of naturally-produced L-arabinose isomerase has higher cost, is difficult to purify, and the like, and is good for large-scale production of the L-arabinose isomerase.

The present disclosure relates to an enzyme complex of arabinose isomerase, agarase and 3,6-anhydro galactosidase and a method for producing tagatose by degrading agar using the same. By using the enzyme complex according to the present disclosure, agar obtained from marine biomass can be degraded effectively and useful physiologically active substances such as tagatose can be obtained effectively therefrom.

Disclosed are components and methods for preparing tagatose from galactose via isomerization reactions using engineered components. The engineered components include microbial cells and methods for preparing microbial cells that have been engineered to catalyze isomerization of galactose to tagatose, in which the microbial cells express cytoplasmically an exogenous L-arabinose isomerase enzyme. The disclosed microbial cells may further be modified for use in methods for preparing tagatose from galactose via isomerization reactions where the microbial cells are treated with reagents that permeabilize the cells. The disclosed methods enable isomerization reactions of galactose to tagatose at relatively high rates, high conversions, and elevated temperatures.