Gessesse, Amare (PhD)Mekonnen, Miraf2019-04-102023-11-082019-04-102023-11-082018-01-01http://etd.aau.edu.et/handle/123456789/17775Gelatinases are enzymes used to hydrolyze gelatin into peptides and amino acids. Enzymatic hydrolysis of gelatin increase it’s functional, textural and nutritional characteristics. The hydrolysates have neutral taste, low bloom and contain high amount of purified protein. In recent years gelatin hydolysates find a number of increasing applications in food and none food products. The main objective of this study was to isolate gelatinase enzyme from soil bacteria and optimize the reaction condition for gelatin hydrolysis. A total of 100 bacterial isolates were isolated from soil samples collected around Addis Ababa University (Arat Kilo Campus) and water samples collected from Lake Afdera. All isolates were screened for the production of gelatinase on gelatin containing media. Based on the properties of the enzyme, one isolate designated as aau17 was selected for further study. The organism can grow under solid-state fermentation and produce gelatinase enzyme with high activity using wheat bran as a carbon source. The enzyme was optimally active at a temperature of 50oC and at pH 8. The optimum enzyme production under solid state fermentation includes an incubation period of 120 h and a moisture content of 66.7%. The isolate produced more enzymes up on addition of peptone as a nitrogen source. The enzyme was used to produce gelatin hydrolysate by hydrolyzing animal bone, animal skin, animal hooves and commercial gelatin. The production process for the gelatin hydrolysis was optimized by varying enzyme concentration and incubation time. The hydrolysis has maximum activity at 4 h incubation period and at high amount of enzyme concentration. This study indicated that by using product of animal waste can be converted to useful gelatin hydrolysates using microbial gelatinases for various applications.enGelatinaseHoovesHydrolysisThesis