title: Production and recovery of an alkaline exo-polygalacturonase from Bacillus subtilis RCK under solid-state fermentation using statistical approach.
abstract: The empirical models developed through two independent RSM (RSM-I, 2(3); RSM-II, 2(5)) in terms of effective operational factors of inoculum age, inoculum volume, wheat bran-to-moisture ratio (RSM-I) and contact time, extraction temperature, agitation, fermented bran-to-solvent ratio and SDS (RSM-II) were found adequate to describe the optimization of exo-polygalacturonase from Bacillus subtilis RCK under solid-state fermentation (SSF) conditions. Through the analysis of RSM-I, wheat bran-to-moisture ratio and inoculum volume were found to be the most significant factors and an increment in both had a positive effect in enhancing enzyme yield, while in RSM-II all the factors significantly affected enzyme recovery except fermented bran-to-solvent ratio, which had the least impact within the ranges investigated in enhancing enzyme recovery. Based on contour plots and variance analysis, optimum operational conditions for maximum exo-polygalacturonase yield were achieved when 1.5% (v/w) of 24h old (OD(600 nm) approximately 2.7+/-0.2) B. subtilis RCK cells were inoculated on moistened wheat bran (1:7 solid substrate-to-moisture ratio) and enzyme was harvested by addition of solvent (1:6 fermented bran-to-solvent ratio) under shaking conditions (200 rpm) in presence of SDS (0.25% w/v) for 15 min at 35 degrees C. An over all 3.4 fold (1.7-fold RSM-I; 2.0 fold RSM-II) increase in enzyme production was attained because of optimization by RSM.
authors: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
authors: Shefali
authors: S
authors: Gupta
authors: Mukesh
authors: M
authors: Kapoor
authors: Krishna Kant
authors: KK
authors: Sharma
authors: Lavanya M
authors: LM
authors: Nair
authors: Ramesh Chander
authors: RC
authors: Kuhad
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D011096:Polygalacturonase / Q000235:genetics / Q000378:metabolism*
chemical_list: D011096:Polygalacturonase