Abstract

COMPARATIVE STUDY OF AK MUTANT STRAIN OF CORYNEBACTERIUM GLUTAMICUM IN FREE AND IMMOBILIZED CELLS

Meenu Singh*, Govind Mohan and D. Muralidhara Rao

ABSTRACT

Productivity of L-lysine at industrial scale is strongly affected by various parameters like the growth rate of a strain, the rate of sugar utilization, the culture conditions, etc. Many researchers have been trying to optimize the variables of fermentation in order to improve the production and yield of L-lysine. The present study dealt with the optimization of various parameters involved in fermentation of free and immobilized cells of AK (Aspartokinase) mutants Corynebacterium glutamicum ATCC 13032. These cells exhibited greater L-lysine production with 30.85 g/l and lysine yield 0.357 than free cells with 25.43 g/l and 0.257 respectively at 96 h. The results of the study suggested that under similar fermentation conditions, immobilized cells of Corynebacterium glutamicum were significantly better candidate for industrial L-lysine production compared to the free cells. The optimized parameters were 30 ° C temperature, 7.5 pH, agitation speed of 200 rpm, 1 vvm air flow rate with glucose concentration of 90 g/l to achieve maximum yield of L-lysine.

Keywords: AK (Aspartokinase) mutant, Corynebacterium glutamicum, Fermentation, Llysine.