Solid-substrate bioprocessing of cow dung for the production of carboxymethyl cellulase by Bacillus halodurans IND18

Abstract

The production of carboxymethyl cellulase (CMCase) by Bacillus halodurans IND18 under solid substrate fermentation (SSF) using cow dung was optimized through two level full factorial design and second order response surface methodology (RSM). The central composite design (CCD) was employed to optimize the vital fermentation parameters, such as pH of the substrate, concentration of nitrogen source (peptone) and ion (sodium dihydrogen phosphate) sources in medium for achieving higher enzyme production. The optimum medium composition was found to be 1.46% (w/w) peptone, 0.095% (w/w) sodium dihydrogen phosphate and pH 8.0. The model prediction of 4210IU/g enzyme activity at optimum conditions was verified experimentally as 4140IU/g. The enzyme was active over a broad temperature range (40–60±1°C) and pH (7.0–9.0) with maximal activity at 60±1°C and pH 8.0. This study demonstrated the potential of cow dung as novel substrate for CMCase production.