Peptones in Silage from Tilapia (Oreochromis niloticus) and Cobia (Rachycentron canadum) Waste as a Culture Medium for Bioprocesses

This study investigated the efficacy of the aqueous fraction obtained after fractionating silage of tilapia (Oreochromis niloticus) and cobia (Rachycentron canadum) in supporting the growth of Escherichia coli and Staphylococcus aureus. The silages were prepared using combinations of citric, formic, and propionic acids. The aqueous fractions, used as test peptones, contained lower levels of total protein. The concentrations of 18 amino acids in all the samples were observed to be lower than those in the commercial peptone. Glutamic acid, lysine, glycine, and aspartic acid were present in higher concentrations than other amino acids, for both types of silage. Biomass production from E. coli culture ranged from 38.4 to 65.9 mg 100 mL^?1 for all the tested treatments, while that for S. aureus was from 26.3 to 53.7 mg 100 mL^?1. This indicated that products from fish silage were effective for bacterial growth in terms of biomass, by providing the main sources of nitrogen and carbon to facilitate their growth. The tested silages yielded similar efficiency to the commercial peptone. The findings revealed that it is feasible for the fish processing industry to incorporate freeze-dried by-products obtained after fractioning waste silage from the processing of tilapia and cobia.