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J M Lebeault - One of the best experts on this subject based on the ideXlab platform.
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Folate requirements of the 2-keto-l-gulonic acid-Producing Strain Ketogulonigenium vulgare LMP P-20356 in l-sorbose/CSL medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto- l -gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l -sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto- l -gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
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folate requirements of the 2 keto l gulonic acid Producing Strain ketogulonigenium vulgare lmp p 20356 in l sorbose csl medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto-l-gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l-sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto-l-gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
S Leduc - One of the best experts on this subject based on the ideXlab platform.
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Folate requirements of the 2-keto-l-gulonic acid-Producing Strain Ketogulonigenium vulgare LMP P-20356 in l-sorbose/CSL medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto- l -gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l -sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto- l -gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
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folate requirements of the 2 keto l gulonic acid Producing Strain ketogulonigenium vulgare lmp p 20356 in l sorbose csl medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto-l-gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l-sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto-l-gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
J C De Troostembergh - One of the best experts on this subject based on the ideXlab platform.
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Folate requirements of the 2-keto-l-gulonic acid-Producing Strain Ketogulonigenium vulgare LMP P-20356 in l-sorbose/CSL medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto- l -gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l -sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto- l -gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
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folate requirements of the 2 keto l gulonic acid Producing Strain ketogulonigenium vulgare lmp p 20356 in l sorbose csl medium
Applied Microbiology and Biotechnology, 2004Co-Authors: S Leduc, J C De Troostembergh, J M LebeaultAbstract:In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto-l-gulonic acid-Producing Strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the Strain when cultured in an l-sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the Strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto-l-gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.
Zhi Nan Xu - One of the best experts on this subject based on the ideXlab platform.
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generation of high rapamycin Producing Strain via rational metabolic pathway based mutagenesis and further titer improvement with fed batch bioprocess optimization
Biotechnology and Bioengineering, 2010Co-Authors: Wei Zhang, Xiyang Chen, Yanwen Duan, Hu Wu, Zhi Nan XuAbstract:Rapamycin is a triene macrolide antibiotic produced by Streptomyces hygroscopicus. Besides its wide application as an effective immunosuppressive agent, other important bioactivities have made rapamycin a potential drug lead for novel pharmaceutical development. However, the low titer of rapamycin in the original producer Strain limits further industrialization efforts and restricts its use for other applications. Predicated on knowledge of the metabolic pathways related to rapamycin biosynthesis in S. hygroscopicus, we have rationally designed approaches to generate a rapamycin high producer Strain of S. hygroscopicus HD-04-S. These have included alleviation of glucose repression, improved tolerance towards lysine and shikimic acid, and auxotrophy of tryptophan and phenylalanine through the application of stepwise UV mutagenesis. The resultant Strain produced rapamycin at 450 mg/L in the shake flask scale. These fermentations were further scaled up in 120 and 20,000 L fermentors, respectively, at the pilot plant. Selected fermentation factors including agitation speed, pH, and on-line supplementation were systematically evaluated. A fed-batch strategy was established to maximize rapamycin production. With these efforts, an optimized fermentation process in the larger scale fermentor was developed. The final titer of rapamycin was 812 mg/L in the 120 L fermentor and 783 mg/L in the 20,000 L fermentor. This work highlights a high rapamycin Producing Strain derived by mutagenesis and subsequent screening, fermentation optimization of which has now made it feasible to produce rapamycin on an industrial scale by fermentation. The strategies developed here should also be applicable to titer improvement of other important microbial natural products on an industrial scale. Biotechnol. Bioeng. 2010;107: 506–515. © 2010 Wiley Periodicals, Inc.
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improvement of industry applied rifamycin b Producing Strain amycolatopsis mediterranei by rational screening
Journal of General and Applied Microbiology, 2002Co-Authors: Zhi Nan XuAbstract:An industrially applied rifamycin B-Producing Strain, Amycolatopsis mediterranei XC 1-02, was used for further screening. A special mutation and screening procedure was adopted to select a Strain, which can alleviate the inhibition caused by both aromatic amino acid and p-hydroxybenzoic acid in the pathway of rifamycin B biosynthesis as well as enhance the production of propionate, one of the precursors of rifamycin B biosynthesis. By the above methods, a Strain A. mediterranei XC 9-25 was obtained, and its rifamycin B productivity in shaking flask reaches 10 g/L, which is 2.38 times higher than that of the ancestral Strain XC 1-02. The productivity of rifamycin B fed-batch fermentation in 60,000 L fermentor with A. mediterranei XC 9-25 reached 19.11 g/L.
D P Labeda - One of the best experts on this subject based on the ideXlab platform.
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amycolatopsis coloradensis sp nov the avoparcin ll av290 Producing Strain
International Journal of Systematic and Evolutionary Microbiology, 1995Co-Authors: D P LabedaAbstract:The Strain that produces the glycopeptide antibiotic avoparcin (LL-AV290) has been described previously as a Strain of “Streptomyces candidus.” Morphological and chemotaxonomic properties of this Strain are typical of the genus Amycolatopsis. The results of a study of the physiological properties of this organism and its levels of DNA relatedness to previously described Amycolatopsis species supported the decision to describe a new species for this Strain, for which the name Amycolatopsis coloradensis is proposed. The type Strain of A. coloradensis is NRRL 3218.
