Culture Conditions for the Production of l-Glutamic Acid from n-Paraffins by Glycerol Auxotroph GL-21

A novel process for the microbial production of l-glutamic acid on an industrial scale was successfully established by using a glycerol auxotroph.

The most suitable carbon source for producing L-glutamic acid was n-paraffins (C₁₃–C₁₅). The production of L-glutamic acid was not affected by a large amount of biotin or oleic acid in the absence of penicillin, and occurred maximally at the glycerol concentration of 0.02% at pH 6.6. The most effective temperature was 28°C.

Under optimal conditions in a 200 liter fermentor, the mutant produced 72 g/liter of L-glutamic acid. On the other hand, the parent produced 53 g/liter of L-glutamic acid in the presence of penicillin.

It is believed that the low productivity of L-glutamic acid by the parent strain was mainly due to the occurrence of the marked decrease in the viable cell counts at the later phase of the fermentation caused by the action of penicillin added.