Gelatin production using fish wastes by extracted alkaline protease from Bacillus licheniformis

An effort was made to produce gelatin from Common carp wastes using extracted alkaline protease from Bacillus licheniformis PTCC 1595. Fermentation was performed by submerged media for 48 h and 72 h. The hydrolyzing enzyme was added in 5, 10, 15, 20, and 25 units per gram of wastes powder for hydrolysis. The produced gelatin was compared with commercial bovine gelatin with regard to some rheological and physicochemical properties. The yield of gelatin production was also determined as a result of hydroxyproline extraction from fish wastes. SDS-PAGE was performed for enzyme and gelatins. For enzyme, two bands were achieved with 39 and 10.5 kDa molecular weight which were separated passing through a 15 kDa UF filter. Both gelatins showed β, α1, and α2 chains as basic components, but the fish waste gelatin showed narrow bands. In conclusion, foam expansion and water holding capacity were approximately equal in both gelatin types used for food industry application. The results indicated that using 20 units of enzyme per gram of waste powder was the optimum amount of enzyme application. Further, fish wastes were concluded to be a practical source for gelatin production.