Preparation of peptone from chicken bone residue by using natural pancreas as catalyst

BACKGROUND The cost of peptone is often a major contributor to costs in the fermentation industry. A novel method for preparation of peptone from chicken bone residue by using natural pancreas as catalyst was developed in this study, aiming to provide a way to convert waste into valuable peptone. RESULTS The molecular weight of chicken bone extract (CBE) hydrolyzed with pancreas or its combination with trypsin ranges between 100 and 1000 Da after 4 h of hydrolysis. CBE hydrolyzed with pancreas (5%, w/w) for 4 h shows higher degree of hydrolysis (DH) (23.60%) than that of 0.5% trypsin, and higher polypeptides and free amino acids content than that of 0.5% trypsin and 1% pancreas. Thus, it was selected for yeast, bacteria and fungi incubation, with commercial casein peptone as a control. Saccharomyces cerevisiae shows a similar growth curve in both media during 36 h incubation. Although Bacillus subtilis shows a longer lag phase (14 h) in chicken bone hydrolysate (CBH) than in the control (6 h), significantly higher OD600 in CBH was obtained after 24 h incubation (P<0.05). Both Escherichia coli and Aspergillus oryzae grew better in CBH than in the control. CONCLUSION The proposed process for inexpensive peptone production provides an effective way to utilize animal bone wastes, and the alternative peptone has widespread application in fermentation industry.