Optimization of Cellulase Production by Soil Bacteria Using Statistical Design

Abstract

Cellulase is an enzyme complex which breaks down cellulose to glucose. It has been used widely in commercial food processing, textile industry and laundry detergents. Majority of studies on cellulase production have focused on fungi, with relatively lesser emphasis on bacterial sources. The current study has focused on isolating bacteria from paddy soil, capable of producing free cellulase and optimization of culture media for increasing cellulase production. Cellulase producing bacteria was isolated from paddy soil and was identified using 16S rDNA sequencing and BLAST search. Screening of nutrients and their influence on the cellulase production was studied using a Plackett-Burman design. Five variables (NH 4 ) 2 SO 4 , Cellulose, K 2 HPO 4 , CaCl 2 .2H 2 0, pH were screened to evaluate their effect on cellulase production, of only two variable K 2 HPO 4 andcellulose were found to have significant effect on cellulase production. Two components with significant effect on cellulase production were further optimized with Response Surface Methodology (RSM) using Central Composite Design (CCD).The optimal levels of these medium components determined were K 2 HPO 4 (2g/ml) andCellulose (2g/ml). The enzyme activity with nutritional medium was 0.148 U/ mL, but a 2 fold increase in the cellulase activity in optimized medium was observed.