Optimization of bacteria pectinolytic enzyme production using banana peel as substrate under submerged fermentation

Abstract

The investigation was based on optimizing the cultural conditions of bacteria pectinolytic enzymes indigenous to soil of banana peel dump site. Optimization of cultural conditions was carried out by changing the physico-chemical environment such as pH, temperature, inocula size and substrate concentration of the production medium by testing for one factor at a time. Highest pectinase activity was observed at pH 6.0 which gave 1.455±0.095 U/mL and 1.695±0.01 U/mL for Bacillus subtilis TYg4-3 and Bacillus amyloliquefaciens SW106 respectively. The optimized temperature for better yield was obtained at 37⁰C with 0.955±0.006 U/mL for Bacillus subtilis TYg4-3 and 1.098±0.012 U/mL for Bacillus amyloliquefaciens SW106. Lactose yielded 1.655±0.046 U/mL and NH4Cl 1.603±0.005 U/mL activity for Bacillus subtilis TYg4-3, while maltose yielded 1.343±0.062 U/mL and KNO₃ 1.075±0.077 U/mL activity for Bacillus amyloliquefaciens SW106. Bacillus subtilis TYg4-3 produced best at 72 h of incubation giving 1.275±0.006 U/mL and at 36 h incubation for Bacillus amyloliquefaciens SW106 giving 1.345±0.033 U/mL activity. Bacillus subtilis TYg4-3 yielded 2.083±0.008 U/mL and 2.015±0.036 U/mL at 1.5% and 2.0% of inoculum size and substrate concentration respectively. Bacillus amyloliquefaciens SW106 produced best enzyme activity at 2.0% of inoculum and substrate concentration and gave 2.193±0.175 U/mL and 2.256±0.067 U/mL enzyme activities respectively.