303 results about "Wild type strain" patented technology

The present invention relates to novel rumen bacterial mutants resulted from the disruption of a lactate dehydrogenase gene (ldhA) and a pyruvate formate-lyase gene (pfl) (which are involved in the production of lactic acid, formic acid and acetic acid) from rumen bacteria; a novel bacterial mutant (Mannheimia sp. LPK7) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (pfl), a phosphotransacetylase gene (pta), and a acetate kinase gene (ackA); a novel bacterial mutant (Mannheimia sp. LPK4) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (pfl) and a phosphoenolpyruvate carboxylase gene (ppc) involved in the immobilization of CO2 in a metabolic pathway of producing succinic acid; and a method for producing succinic acid, which is characterized by the culture of the above mutants in anaerobic conditions. The inventive bacterial mutants have the property of producing succinic acid at high concentration while producing little or no organic acids, as compared to the prior wild-type strains of producing various organic acids. Thus, the inventive bacterial mutants are useful as strains for the industrial production of succinic acid.

A coryneform bacterium which has an L-glutamic acid-producing ability and grows at least at the same growth rate as a non-mutated strain or a wild-type strain and has intracellular α-ketoglutarate dehydrogenase activity which is less than half that of the non-mutated or wild-type strain, and is obtained by introducing a mutation into a coding region or an expression control region of the chromosomal odhA gene encoding the E1o subunit of the α-ketoglutarate dehydrogenase complex.

An engineered nitrile hydratase-producing bacterium and its construction method as well as its applications, wherein the engineered nitrile hydratase-producing bacterium is a mutant strain of an original nitrile hydratase-producing bacterium strain obtained by knocking-out or inhibiting the amidase gene in the original strain. The construction method of the engineered bacterium is to block the expression of the amidase gene by inserting the large fragment of a recombinant suicide plasmid carrying an amidase gene fragment into a wild-type strain through the homologous recombination between the recombinant suicide plasmid and the amidase gene of the wild-type strain. Compared to the corresponding wild-type bacterium strain, both the cell growth and the nitrile hydratase expression of the engineered nitrile hydratase-producing bacterium according to the invention are increased. In the process of catalyzing the hydration of acrylonitrile to produce acrylamide, the yield of the product, acrylamide, is significantly increased, while the yield of the by-product acrylic acid is significantly decreased. The engineered nitrile hydratase-producing bacterium of the present invention has wide application prospect in the production of acrylamide by microbiological process.

The invention relates to a microbial strain which can produce sphingosine, dihydrosphingosine, phytosphingosine and / or the derivatives thereof with improved level. In addition, the invention further discloses a method which is based on induced mutation or other selection technologies, and the strain is prepared accordingly. As an example, a mutant strain of pichia pastris is provided; and compared with the wild-type strain, compounds produced by the mutant strain are higher by about 50 percent.

The invention relates to a construction way for toxic gene deletion of a wild Listeria monocytogenes (short as LM). After expanding homogenetic sectionsactA and plcB at two wings of the genes to be deleted, the actA and plcB are spliced by SOEing PCR method, inserted into a penetrating carrier pKSV7, introduced by electric transferring into Listeria monocytogenes, so as to get Listeria monocytogenes yzu LM1-2 with actA and pclB deleted, the preservation no. for the Listeria monocytogenes yzu LM1-2 is CCTCC NO: M206107. The invention solves the pathogen for human being and animals of Listeria monocytogenes, high death rate and pollution and harm of LM on food. The invention deletes actA and plcB, hence reduces the toxicity of the wild bacterial strain yzu LM4.

Provided are novel rumen bacterial mutants resulted from the disruption of a lactate dehydrogenase gene (ldhA) and a pyruvate formate-lyase gene (pfl) from rumen bacteria; a novel bacterial mutant (Mannheimia sp. LPK7) having disruptions of a ldhA, a pfl,a phosphotransacetylase gene (pta), and a acetate kinase gene (ackA); a novel bacterial mutant (Mannheimia sp. LPK4) having disruptions of a ldhA, a pfl, and a phosphoenolpyruvate carboxylase gene (ppc) involved in the immobilization of CO2 in a metabolic pathway of producing succinic acid; and a method for producing succinic acid, characterized by culture of the above mutants in anaerobic conditions. The bacterial mutants have the property of producing succinic acid at high concentration while producing little or no organic acids, as compared to the prior wild-type strains of producing various organic acids. Thus, the bacterial mutants are useful as strains for the industrial production of succinic acid.

The invention discloses an engineering bacteria for producing 1,3-propylene glycol and a method for constructing the same. The invention silences the phosphate transacetylase genes in a wild type strain producing 1,3-propylene glycol by utilizing a homologous recombination method and a gene insertional inactivation method so as to obtain a genetically engineered bacterium, of which the acetic acid metabolic pathway is blocked. When the 1,3-propylene glycol is fermented and produced by the engineering bacteria disclosed by the invention, the acetic acid production is largely reduced, the toxic action on cells caused by the by-product acetic acid is greatly decreased and the production rate of biomass per unit is enhanced. Moreover, the post-extracting process is simplified and the production cost is reduced as the species of the by-products are reduced. The experiments prove that the concentration of the 1,3-propylene glycol can reach more than 55g / L by fermenting the engineering bacteria provided by the invention for 28 hours according to a conventional method. The invention plays an important role in the industrial production for producing 1,3-propylene glycol by a microbiological fermentation method and has a wide application prospect.

The invention discloses an engineering bacteria of inactivated acetolactate synthetase, and a construction method and applications thereof in producing 1,3-propanediol. The acetolactate synthetase in wild type strain for producing 1,3-propanediol is silenced by utilizing homologous recombination and gene insertion inactivation methods, thus obtaining 2,3-butanediol metabolic pathyway-blocked engineering bacteria. By using the engineering bacteria to ferment and produce 1,3-propanediol, the production of side product 2,3-butanediol can be greatly reduced, the metabolism shunting effect of the side product 2,3-butanediol can be greatly decreased, and the conversion rate for producing 1,3-propanediol can be improved; in addition, the side product 2,3-butanediol is reduced to lower the post-extraction pressure, so that the production cost can be lowered. Proved by experiments, the concentration of 1,3-propanediol can achieve 72g / L by fermenting the engineering bacteria for 36 hours through adopting a conventional method. The engineering bacteria and the construction method and applications thereof can play an important role in the industrial production of 1,3-propanediol through adopting a microbial fermentation method, and have wide application prospects.

Mutant photosynthetic microorganisms having reduced chlorophyll and increased photosynthetic efficiency are provided. The mutant strains have mutated chloroplastic SRP54 genes and exhibit increased productivity with respect to wild type strains. Also provided are mutant algal strains having mutated cytosolic SRP54 genes. Provided herein are methods of producing biomass and other products such as lipids using strains having mutations in an SRP54 gene. Also included are constructs and methods for attenuating or disrupting SRP54 genes.

The present invention relates to a gene of swine vesicular disease virus (SVDV) and the mutant strains of the gene, and the expression plasmids, the preparation process thereof. The invention also relates to a vaccine for use in the prophylaxis of swine vesicular disease composition containing the mutant strains. Furthermore, the invention provides a process for differentiating mutant strains of SVDV from the wild type strain of SVDV, coxsackievirus and foot-and-mouth disease virus by polymerase chain reaction.

The present invention relates to the field of attenuated live viruses useful as vaccine or medicament for preventing or treating Porcine Reproductive and Respiratory Syndrome (PRRS) in swine, and is based on the surprising finding of a PRRS virus which is able to induce the interferon type I response of a cell infected by said virus. In one embodiment, the PRRS virus according to the invention is a PRRS virus mutant comprising, in comparison with the genome of a wild type strain, a mutation in the gene encoding the non structural protein 1 (nsp1) of said virus.

The invention discloses a watermelon oxysporum pathogenic FonAGL3 gene as well as a deleted DNA fragment, a deletion mutant and application thereof, and aims to solve the technical problem of biological prevention and treatment on watermelon oxysporum. A pathogenic gene FonAGL3 derived from watermelon fusarium oxysporum is analyzed and screened by inserting watermelon oxysporum T-DNA into a mutant library, by utilizing the homologous gene replacement principle, DNA fragments of the target gene FonAGL3 are replaced by gene DNA fragments of a resistance gene hygromycin B (HPH), a FonAGL3 gene deletion mutant is obtained by establishing a gene deletion carrier and implementing genetic transformation of a wild strain FON-11-06, and the FonAGL3 mutant bacterium has a good wilt prevention and treatment effect and is environmental-friendly and low in prevention and treatment cost.

The invention relates to an endogenous bacillus subtilis positive mutant strain, a preparation method thereof, a prepared biocontrol agent and an application of the biocontrol agent in preventing and controlling pomegranate dry rot, including (1) screening of a Bacillus subtilis wild-type strain NS04 and ultraviolet mutation and breeding of a positive mutant biocontrol strain NS04307; (2) antibacterial stability of the positive mutant strain NS04307; (3) a preparation method of the positive mutant strain NS04307 biocontrol agent; and (4) application of the positive mutant strain NS04307 in preventing and controlling plant diseases. The biocontrol agent disclosed by the invention has the characteristics of wide bactericidal spectrum, good effect, difficulty in disease drug resistance generation, safety on human, livestock and crops, environmental friendliness and the like and has a better effect on the field control of the pomegranate dry rot especially. In addition, the biocontrol agent disclosed by the invention achieves outstanding inhibition activity on the growth of 15 different pathogenic bacteria, such as Sclerotiumrolfsii, Trichotheciumroseum, Exserohilumrostratum, Fusariumoxysporum, Alternariaalternate and the like.

The invention discloses double-gene knockout engineering bacteria and a construction method and an application thereof in fermentation production of 1,3-propylene glycol. A D-lactic dehydrogenase gene and an alpha-acetolactate synthetase gene in a genome of a wild type strain for production of 1,3-propylene glycol are knocked out to obtain the engineering strain; the wild type strain for production of 1,3-propylene glycol takes glycerol as a raw material for fermentation production of 1,3-propylene glycol. The engineering bacteria obtained after simultaneous knockout of the two genes of lactic dehydrogenase and acetolactate synthetase are applied in the process of fermentation-process production of 1,3-propylene glycol; the accounting proportion of 1,3-propylene glycol in a fermentation liquid in metabolites is increased, synthesis of lactic acid and 2,3-butylene glycol are simultaneously greatly reduced, and other by-products are not significantly increased. In the process of microbiological fermentation-process production of 1,3-propylene glycol, the role in improving the accounting proportion of 1,3-propylene glycol synthesized by the engineering bacteria and reducing the proportion of the synthesized by-products are played, the production cost is facilitated to be reduced, and the engineering bacteria have important application prospects.

A method is provided for identifying, isolating, and producing htrB mutants of gram-negative bacterial pathogens. The method comprises mutating the htrB gene of a gram-negative bacterial pathogen so that there is a lack of a functional htrB protein, resulting in a mutant that lacks one or more secondary acyl chains contained in the wild type gram-negative bacterial pathogen, and displays substantially reduced toxicity as compared to the wild type strain. Also, the present invention provides methods for using a vaccine formulation containing the htrB mutant, the endotoxin isolated therefrom, or the endotoxin isolated therefrom which is then conjugated to a carrier protein, to immunize an individual against infections caused by gram-negative bacterial pathogens by administering a prophylactically effective amount of the vaccine formulation.

The present invention relates to a method for rapidly detecting quinolone-resistant Salmonella spp. The invention also relates to the oligonucleotide primers and probes utilized in the method, which can differentiate mutant strains having one or two single point mutations in gyrA gene or single point mutation in parC gene from wild type strains, respectively. Said primers and probes can be effectively used for detection of nalidixic acid-resistant and / or ciprofloxacin-resistant Salmonella strains.

The present invention belongs to the field of antibiotic gene engineering, and is especially the process of cloning nicomycin biological synthetic gene sanU from one strain of Streptomyces ansochromogenes 7100 CGMCC 4.321; connecting the synthetic gene sanU with promoter of melanin biosynthetic structure gene, cloning onto the polycloning site of integrative single-copy plamid, transforming wild Streptomyces ansochromogenes 7100 CGMCC 4.321 protoplast to obtain nicomycin X component of the recombinant engineering bacterium in the yield 2 times higher than wild strain. The high-yield engineering bacterium may be used in preparing antiseptic medicines.

The invention discloses application of a guided glycosyltransferase gene, namely application of the guided glycosyltransferase gene cps2E and cps4E in improving lactobacillus plantarum extracellular polysaccharide synthesis; the cps2E and cps4E genes and a temperature-sensitive plasmid pFED760 are recombined to construct a knockout vector, the knockout vector is guided into food-borne lactobacillus plantarum competent cells, and then by means of homologous recombination, cps2E and cps4E genes are constructed to knock out strains YM 4-3-deltacps2E, YM 4-3-deltacps4E and YM 4-3-deltacps2E-4E; the capacity of the strains producing extracellular polysaccharide is determined through a phenol-sulfuric acid method, it is found that the capacity of knocking out extracellular polysaccharide produced by the strains is lower than that of wild type strains, and the double knockout strain extracellular polysaccharide yield is very low, so that the cps2E and cps4E genes play a key role in the extracellular polysaccharide synthesis, and the application has great potential in extracellular polysaccharide biosynthesis research and application fields.

The invention provides a red monascus alpha-amylase gene as well as a preparation method and application thereof. According to the technical scheme, an amylase protein expression gene highly homologous with the monascus alpha-amylase A is obtained through the screening in the red monascus NRRL1597 whole genome; a PCR amplification method is designed around the sequence feature. On the basis, the red monascus CICC41233 is used as an experiment strain; PCR amplification is performed to obtain a target gene; then, the target gene is used for building a dual plasmid expression vector pNeo0380-440333; then, through agrobacterium tumefaciens EHA105 mediation, the vector is transferred into the parent red monascus to obtain a red monascus high-yield strain. The strain can obviously promote the degradation of starch rice, so that the yield of the red monascus can be improved. On the basis, a special fermentation method for red monascus production is designed around the biological characteristics of the recombination strain; the production yield of the red monascus is obviously higher than that of a wild strain; meanwhile, the proportion of ethanol-soluble ingredients in the red monascus isimproved.

The invention provides a DNA sequence of a phytoene desaturase gene of sphingomonas sp., a recombinant strain with phytoene desaturase lost and application thereof. The phytoene desaturase gene (crtI) of the sphingomonas sp. has a nucleotide sequence shown by SEQ ID No.1. The DNA sequence of the phytoene desaturase gene (crtI) of the sphingomonas sp. provided by the invention lays a foundation for the genetic transformation of a biological synthesis manner of sphingomonas sp. carotene. Moreover, compared with the wild strains, the sphingomonas sp. recombinant strain with the phytoene desaturase lost, which is constructed by a gene knockout method, has gellan glue yield unchanged, generates no uranidin, reduces the amount of ethanol or isopropanol which is used during gellan glue extraction and therefore reduces the production cost of the gellan glue; meanwhile, the strain can also be applied to the further gene knockout or metabolic engineering transformation.

In preferred embodiments, the present invention provides new isolated strains of a Geobacter species that are capable of using a carbon source that is selected from C3 to C12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. In other aspects, other preferred embodiments of the present invention include methods of making such strains and methods of using such strains. In general, the wild type strain of the microorganisms has been shown to be unable to use these C3 to C12 organic compounds as electron donors in metabolic steps such as the reduction of metallic ions. The inventive strains of microorganisms are useful for improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic devices, and electric vehicles.

We describe the use of chemically defined media for the fermentative production of valuable compounds on an industrial scale. Microbial strains which are suitable for fermentation on an industrial scale using a chemically defined medium include fungal, yeast and bacterial strains. Suitable strains can be obtained as wild type strains or by screening and selection after mutagenic treatment or DNA transformation.

The invention discloses application of a dihydropteroate synthase gene folP, namely the application of the dihydropteroate synthase gene folP in improvement of folic acid biosynthesis of microbial strains or in increase of biomass of the microbial strains. A knockout vector is created by recombination of the gene folP and a temperature-sensitive plasmid pFED760, and is introduced into a competentcell of food-borne lactobacillus plantarum, and accordingly, an folP gene knockout strain is formed by homologous recombination. Results show that the folP gene is related to the cell morphology and the growth state of the strains; the folic acid production ability of the delta folP strains is found to be lower than that of wild-type strains through liquid chromatography-mass spectrometry, so thatthe folP gene plays a key role in folic acid synthesis; the folP gene has great potential in research and application of the folic acid biosynthesis.

The invention relates to an optimization method of culture conditions of alkaline pectinase gene engineering bacteria, comprising the following steps: (1) adopting a single-factor experiment to optimize the fermentation medium formation of the alkaline pectinase gene engineering bacteria to obtain a preliminarily optimized fermentation medium; (2) optimizing a target strain medium with a response surface methodology to obtain the target strain medium; and (3) optimizing the fermentation culture conditions to the target strain by a post-optimizing medium to obtain the optimization culture conditions. The invention gropes a set of optimal fermentation culture conditions to ensure that enzymatic activity produced by engineering bacteria fermentation reaches 758.7825U / ml which is improved by 50 times compared with the activity of alkaline pectinase produced by original wide strains and is improved by 3 times compared with the enzymatic activity of alkaline pectinase produced by LB fermentation medium fermentation gene engineering bacteria, so that the invention has an important meaning for improving the market competitiveness of industrial enzyme.

The present invention belongs to the field of a biological technique and relates to a RNA polymerase mutant of Bacillus spp CC09 bacterial strain of high-yield antimycotics cyclic lipopeptides substances screened by using a LB plate containing rifampin (50 mug / ml). The mutation site of the mutant is on any position of 485-490 in a RNA polymerase beta sub-unit amino acid sequence, Compared with wild type CC09 bacterial strain, the output of antimycotics cyclic lipopeptides antibiotics Iturin and Surfactin produced by the mutant can be increased by 100%-300%, the antifungal activity is increased by 20-60%, and the mutant can be used for preventing and treating a plurality of crop diseases.

The present invention relates to novel rumen bacterial mutants resulted from the disruption of a lactate dehydrogenase gene (ldhA) and a pyruvate formate-lyase gene (pfl) (which are involved in the production of lactic acid, formic acid and acetic acid) from rumen bacteria; a novel bacterial mutant (Mannheimia sp. LPK7) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (pfl), a phosphotransacetylase gene (pta), and a acetate kinase gene (ackA); a novel bacterial mutant (Mannheimia sp. LPK4) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (pfl) and a phosphoenolpyruvate carboxylase gene (ppc) involved in the immobilization of CO2 in a metabolic pathway of producing succinic acid; and a method for producing succinic acid, which is characterized by the culture of the above mutants in anaerobic conditions. The inventive bacterial mutants have the property of producing succinic acid at high concentration while producing little or no organic acids, as compared to the prior wild-type strains of producing various organic acids. Thus, the inventive bacterial mutants are useful as strains for the industrial production of succinic acid.

The invention discloses extreme halophilic archaea engineering bacteria for producing bioplastics PHBV (Poly-(HydroxyButyrate-co-Hydroxy Valerate)) by effectively utilizing a carbon source. The recombined extreme halophilic archaea is extracellular polysaccharide synthesis function-deficient engineering bacteria obtained by deleting at least one protein function expressed by an extracellular polysaccharide synthesis cluster in the genome of the extreme halophilic archaea Haloferax mediterranei. The extreme halophilic archaea has the advantages that infectious microbe is not easy to pollute, PHA (Poly Hydroxy Alkanoate) is convenient to extract, the PHBV from a non-correlated carbon source can be synthesized, and the like, and is considered as a highly preponderant PHBV producing strain. The extracellular polysaccharide synthesis function-deficient strain engineering bacteria are characterized in that the polyhydroxyalkanoate can be produced from various carbon sources such as glucose, starch and whey more efficiently in contrast with a wild type strain, the concentration of the PHBV is 20% higher than that of the wild type strain under the same fermentation conditions, and the problems such as sticking, lots of bubbles and dissolved oxygen reduction of a culture solution caused by extracellular polysaccharide accumulation are also solved.

The invention provides a recomposed large intestine Escherichia coli expressing adenosine methionine synthetase with CGMCC No. 2299 and the composition method of the recomposed large intestine Escherichia coli. The invention further provides a recomposed expression carrier pMETK of adenosine methionine synthetase. In the recomposed large intestine Escherichia coli expressing adenosine methionine synthetase with CGMCC No. 2299, the expression quantity of the adenosine methionine synthetase accounts for 31.36 percent of soluble albumen of the strain, the activity of the adenosine methionine synthetase expressed is as high as 7.38U / ml, far higher than that of wild type strains.