Isolation of A Novel Collagenase-producing Strain from Animal Bone Wastes and Optimization of Its Enzyme Production

Abstract

A collagenase-producing bacterium was isolated and identified from animal bone wastes. Based on its morphological, physiological and biochemical characteristics, and 16S rRNA gene phylogenetic tree analysis, the strain was identified belonging to Bacillus cereus and named as MBL13. The conditions of culture medium and fermentation were optimized. The results indicated that sucrose, bone gelatin and Ca2+ were optimal carbon, nitrogen sources and metal ion for B. cereus MBL13. By response surface methodology (RSM), the optimum fermentation conditions were made of temperature 33.8 C, fermentation time (X2) of 49.5 h, inoculum concentration (X3) of 45.2 mg/L, medium volume (X4) of 27.3 mL, and initial pH (X5) of 6.8 with the maximum collagenase activity of 50.03 U/mL. From the culture supernatant, a novel collagenase was purified and its molecular weight was estimated by SDS-PAGE to be approximately 52.0 kD. Scanning electron microscopy (SEM) analysis showed that the purified collagenase could effectively degrade bovine bone collagen. This study suggested the collagenase produced by B. cereus MBL13 has a great potential as a novel protease in hydrolyzing animal bone wastes.