The influence of surfactants and bivalent metals on L-lysine production by Bacillus subtilis using agricultural products as carbon and nitrogen sources

Abstract

The influence of surfactants and bivalent metal ions on L-lysine production by Bacillus subtilis using agricultural products as carbon and Nitrogen sources was studied. 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, biochemical and molecular characteristics. Optimization of some parameters which included, surfactants and bivalent metal on L-lysine production by B. subtilis was carried out. The L-lysine was produced in 100 ml flasks containing fermentation media FM1 and FM2. The findings revealed that, enhanced lysine yield of 3.30 mg/ml and 1.46 mg/ml by B. subtilis PR13 and B. subtilis PR9, was observed in the presence of 0.1 µg/ml of stearic acid and 0.1% v/v Tween 80 respectively. The supplementation of 5 µg/ml of CuSO4 and 1 µg/ml of NiCl2, enhanced optimum L-lysine yield of 3.18 mg/ml for B. subtilis PR 13 and 1.51 mg/ml for B. subtilis PR9 respectively. The results obtained in the study illustrated that the optimization of process parameters could increase the L-lysine yield by B. subtilis PR13 and B. subtilis PR9.