Production of multi enzyme preparation by Bacillus subtilis using mosambi peel as substrate

Aim: To determine feasibility of using mosambi peel as substrate for multi enzyme production through microbial intervention. Methodology: Thirty-three bacterial isolates were isolated from biodegradable organic substrates and investigated in-vitro their biodegradable activities viz. pectinolytic, cellulolytic and amylolytic. The best performing bacterial isolate, exhibiting aforesaid activities were selected and identified using 16S rRNA technique. The factors, that influenced the fermentation, viz. temperature, pH and incubation period of bacterial culture were optimized for maximum production of multi enzymes viz. pectinase, cellulase and amylase using mosambi peel as substrate under solid-state fermentation conditions. Molecular weights of different enzymes present in multi-enzyme preparation were determined by SDS PAGE. The juice extraction efficiency of crude multi enzyme preparation was compared with that of pure commercial enzyme. Results: Out of thirty-three bacterial isolates, after primary and secondary screening, the best performing bacterial isolate was identified as Bacillus subtilis strain NG 105 (Genbank accession number MN493055). Higher enzyme activities were observed at pH 7.0, incubation temperature of 35 degrees C and incubation period of 10 days for pectinase, cellulase and amylase using mosambi peel as substrate. The purified enzymes characterized by SDS-PAGE, revealed to have molecular mass of 65 kDa for pectinase, 50 kDa for cellulase and 55 kDa for amylase. Bagasse fibre was found to be the most suited matrix for immobilization. The juice extraction efficiency of partially purified crude multienzyme preparation was 88% of commercial pectinase. Interpretation: Mosambi peel is a suitable substrate for multienzyme production using Bacillus subtilis under solid-state fermentation condition.