Investigation of submerged fermentation of slaughterhouse wastes by proteolytic microbial isolates

The meat industry (livestock, poultry, and fish) produces several tons of waste annually, sometimes with environmental problems. Different parts of these lesions have different types and amounts of protein. One of the current trends in biotechnology is the application of microbial-mediated processes in the valorization of the food industry by-products, including livestock slaughterhouse wastes. The exploitation of keratin proteins from livestock slaughterhouse wastes through microbial processes has been widely discussed in terms of prospects and economic conditions, where proteolytic microorganisms often play a crucial role. Peptides obtained from protein hydrolysates have received special attention from researchers due to their inherent bioactivities. This method is based on some bacteria or yeast species that secrete enzymes (including proteases) in the extracellular growth medium. Therefore, inoculation of protein material with this type of bacterial cell can lead to proteolysis and peptide production. In this study, first, to isolate proteolytic isolates, blood powder, meat powder, a mixture of meat and blood powder, and bone of slaughterhouse waste were screened. Then proteolytic isolates were identified by culturing the isolates obtained in skim milk agar۱% medium and isolates with strong protease properties were selected and used to ferment the wastes. Fermentation was performed by immersion for ۵ days at a temperature of ۳۰℃ and ۱۵۰ rpm by two isolates, B۴, A۵ with strong protease properties. Then the degree of hydrolysis of the hydrolyzed product was estimated based on the OPA method. ۱۳ strains with the ability to grow on wastes powder were identified as carbon sources. A total of ۶ bacterial isolates showed significant proteolytic potential. The results show that the degree of protein hydrolysis by fermentation with A۵ bacteria is significantly increased (P<۰.۰۵) compared to fermentation with B۴ bacteria.

کلیدواژه ها:

Protein hydrolysis ، blood powder ، meat powder ، Screening ، Fermentation