Digestive proteases from fish processing wastes: their partial characterization and comparison

FRIEDMAN IVANA SOLEDAD; BEHRENS LEONEL AGUSTÍN; PEREIRA, NAIR DE LOS ANGELES; CONTRERAS EDGARDO MARTÍN; FERNÁNDEZ GIMENEZ, ANALIA VERÓNICA

JOURNAL OF FISH BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 p. 1 - 11

0022-1112

Fish processing generates plenty of waste that is directly discarded in open-air dumpsand water sources, or treated in the same way as urban solid waste, causing seriouspollution problems. The waste represents a significant source of high-valuebioproducts with potential applications in different industrial processes such as theproduction of feed, fertilizers, biodiesel and biogas, detergent additives and cosmetics. The objective of this study was to characterize and compare specific activitiesunder different pH values and temperature conditions of acid and alkaline proteinases and viscera yield from the following fish species: Argentine hake Merlucciushubbsi, Brazilian flathead Percophis brasiliensis, Brazilian codling Urophycis brasiliensisand Stripped weakfish Cynoscion guatucupa. Individuals were fished off the coast ofMar del Plata (Argentina) by a commercial fleet and the viscera were immediatelyextracted and kept on ice until use. Stomach proteinases from four species had thehighest activity at pH 2, with stability in the range of pH 2?4. The optimum pH was11.5 from intestinal enzymes of C. guatucupa, M. hubbsi and P. brasiliensis and 9.5from intestinal enzymes of U. brasiliensis. Alkaline proteinases from all species werehighly stable in the range of 7?11.5. The optimum temperature of stomach proteinases from the four species studied were 30 and 50C, with stability at 10 and 30Cduring 150 min. The optimum temperature of intestinal enzymes from the testedspecies were 50C with high stability at 10 and 30C during 150 min. Alkaline proteinase from all species and acid proteinases from C. guatucupa were inactive at 70Cafter 150 min, while there was a residual activity lower than 5% at 80C on preincubated stomach enzymes of M.hubbsi, P. brasiliensis and U. brasiliensis after5, 10 and 20 min, respectively. Digestive proteinases recovered in this study couldbe appropriate for technological usage, reducing manufacturing costs, obtaining revenue from fishery wastes, and contributing to the reduction of environmentalpollution.