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 28mg/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.
