The Influence of Vitamins, Antibiotics and Growth Stimulators on L-lysine Production by Bacillus subtilis Using Agricultural Products as Carbon and Nitrogen Sources

Abstract

L-Lysine is one of the 9 amino acids which are essential for human and animal nutrition. It is a basic building block of all proteins and cannot be synthesized biologically in the body. The influence of vitamins, antibiotics and growth stimulators on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources was examined. The L-lysine producing bacteria had already been isolated from Nigerian soil. They were purified and Identified as B. subtilis PR13 and B. subtilis PR9, using cultural and biochemical characteristics. The of influence of vitamins, antibiotics and growth stimulators on L-lysine production by Bacillus subtilis PR13 and 9 was evaluated in 100 ml flasks containing 20 ml fermentation media (FM1 and FM2). The results obtained showed that, an enhanced lysine yield of 3.41 and 1.57 mg/ml by Bacillus subtilis PR13 and Bacillus subtilis PR9, was observed in the presence of 1 µg/ml of biotin and 10 µg/ml respectively. The supplementation of 0.04 units/ml of penicillin, enhanced optimum L-lysine yield of 2.38 mg/ml for B. subtilis PR 13 and 1.64 mg/ml for B. subtilis PR9 respectively. The addition of 0.1% w/v peptone and yeast extract, enhanced optimum L-lysine yield of 2.66 mg/ml for B. subtilis PR 13 and 1.72 mg/ml for B. subtilis PR9 respectively. There was a positive correlation between peptone and L-lysine production by B. subtilis PR13 (r= 0.85) and yeast extract and L- lysine production by B. subtilis PR9 (r= 0.54). The results obtained in the study showed that the supplementation of the fermentation media with some vitamins, antibiotics and growth stimulators enhanced the L-lysine yield of B. subtilis PR13 and B. subtilis PR9.