STATISTICAL OPTIMIZATION OF EXPERIMENTAL VARIABLES ASSOCIATED WITH PRODUCTION OF ALPHA AMYLASES BY BACILLUS SUBTILIS USING BANANA AGRO-RESIDUAL WASTES IN SOLID-STATE FERMENTATION

摘要

The synthesis of α-amylase using Bacillus subtilis, NCIM 2439, was studied using substrate banana waste in the solid-state fermentation medium. The effect of incubation time, inoculum size, initial moisture content, temperature, pH and additional nutrients on the production of alpha-amylase was characterized. The pH, temperature and moisture content in the solid-state fermentation medium were statistically optimized using response surface methodology. A maximum yield of 53.3 U/g was recorded from banana waste with 70% initial moisture content, 8.0 pH, 35°C temperature and additional nutrients (2.0%, ammonium sulphate, 4.0% beef extract, 1.0% glucose and1.0% sodium chloride) in the medium an inoculum to substrate ratio of 20% (v/w) for 24h ncubation. The study provides information on the appropriate temperature, pH and moisture content in the solid-state fermentation, yielding the highest enzyme levels.