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.
Keywords
animal bone wastes, collagenase, isolation, Bacillus cereus MBL13, optimization