Cultural Conditions for l-Leucine Production by Strain No. 218, a Mutant of Brevibacterium lactofermentum 2256 |
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Authors: | Takayasu Tsuchida Fumihiro Yoshinaga Koji Kubota Haruo Momose Shinji Okumura |
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Institution: | Central Research Laboratories, Ajinomoto Co., Inc., Suzuki-cho, Kawasaki, Japan |
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Abstract: | The excellent l-leucine producing mutant No. 218, derived from a biotin requiring glutamic acid producing strain, is methionine and isoleucine auxotrophic. A suboptimum growth condition made by adding a limiting amount of isoleucine was necessary for the maximum production of l-leucine. On the other hand, methionine was indifferent to the productivity if sufficiently supplied for growth.Biotin of more than 50 μg/liter caused the accumulation of l-leucine; less than 50 μg/liter, however, gave a drastic change in accumulation pattern from l-leucine to l-glutamic acid. Strain No. 218 produced 28 mg/ml of l-leucine after 72 hr cultivation when 13 % glucose was supplied as a carbon source, thus giving the yield of 21.6%.Effects on l-leucine production of concentrations of inorganic salts, pH, temperature and aeration were also investigated. |
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Keywords: | aspartokinase L-lysine feedback-inhibition site Escherichia coli lysC |
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