EMPIRICAL OPTIMIZATION OF CULTURE CONDITIONS FOR L-GLUTAMIC ACID PRODUCTION BY CORYNEBACTERIUM GLUTAMICUM X680Abstract
The present investigation was undertaken to improve L-glutamic acid production by a biotin auxotrophic mutant Coryne-bacterium glutamicum X680. For this purpose, culture conditions were optimized. In this regard, different physical and nutritional parameters were examined. The culture was incubated in 100 ml Erlenmeyer conical flasks in an incubator with a shaker at 150rpm. Maximum production was obtained with: pH, 7.0; period of incubation, 72h; volume of medium, 30ml; size of inoculum, 4% (8 × 106 cells); age of inoculum, 48 h; temperature, 30 ºC; glucose, 12g%; urea, 1g%; calcium carbonate, 4g%; biotin, 3µg/ml; potassium dihydrogen phosphate, 0.3g%; dipotassium hydrogen phosphate, 0.3g%; magnesium sulphate, heptahydrate, 2mg%; zinc sulphate, heptahydrate, 10µg/ml; ferrous sulphate, heptahydrate, 10 µg/ml and biotin, 3µg/ml. The production was increased significantly (p<0.01) from 7.4 mg/ml to 27.6 mg/ml.