Tryptophan biosynthesis by genetically engineered Escherichia coli utilizing different carbon sources /
(Pck), and phosphoenolpyruvate synthase (Pps) in a suitable
| Main Author: | |
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| Format: | Thesis eBook |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Summary: | (Pck), and phosphoenolpyruvate synthase (Pps) in a suitable (TktA) activity on aromatics production in Escherichia coli 2-keto-3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) acid for animal species and humans, depends largely on additional nitrogen source was studied: glutamine was not biosynthesis. We also compared the efficiency of glucose, Biotransforrnation of chemically synthesized precursors or both of these processes due to expensive precursors in the can be used more efficiently than glucose with overexpression E. coli host cell. While overexpression of AroG alone with former and low yield in the latter hamper the expected large found to improve neither plasmid stability, nor tryptophan glycerol as carbon sources for L-tryptophan biosynthesis. However, very few attempts were made to optimize precursor improve the yield in fermentative processes have focused on in nature as a major component of lignocellulosic biomass, increased to 14% when xylose was used. In the overexpression level obtained from TrpAE overexpression only, overexpression levels in vivo . While investigation along this line was in market of L-tryptophan. Most of the previous studies to medium increased by 28% in xylose compared to glucose. medium. Use of 0.3% xylose+0.7% pyruvic acid and 0.3% microbial processes due to drawback of chemical synthesis: negative effect on L-tryptophan biosynthesis in xylose nitrogen sources are the major microbial production of TktA together with AroG and TrpAE showed a 90% increase of TrpAE only, the specific uwtophan concentration in the of TzpAE only. On the other hand, TktA and AroG can be over the basal level. The overexpression of neither Pps, nor overexpressed together with TrpAE to get higher yields of Overexpression of either AroG or AroG with TktA had a Pck did not improve Ltryptophan biosynthesis either with production by fermentation from inexpensive carbon and progress in our laboratory, positive effects of transketolase synthase (AroG), TktA, phosphoenolpyruvate carboxykinase techniques used. Unfortunately, high production costs of The commercial production of L-uWtophan, an essential ainino the effects of overexpressing the tryptophan operon (TrpAE), The experimental yield obtained from glucose, of 10% the formation of a racemic mixture of DL-tryptophan. TrpAE improved L-tryptophan biosynthesis 28% over the basal TrpAE or AroG and TktA. The effect of glutamine as an tryptophan biosynthesis, in order to optimize production. tryptophan biosynthesis. We conclude that xylose, abundant tryptophan where glucose is favored as a carbon source. varying the specific activity of key enzymes involved in L- was reported by Draths et. al. In this study, we investigate xylose, 0.3% xylose+0.7% pyruvic acid and 0.3% xylose+0.7% xylose+0.7% glycerol as carbon sources did not improve |
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| Item Description: | "Major subject: Chemical Engineering". Vita. |
| Physical Description: | xi, 49 leaves : illustrations ; 28 cm. Also available online. |
| Bibliography: | Includes bibliographical references. |