Browsing by Author "Getu Abebe"
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Item Isolation and Characterization of Rennin Enzyme from Mucor Species and Utilization for Cheese Making(Addis Ababa University, 2006-01-31) Getu Abebe; Abate Dawit (PhD)Microbial milk-clotting enzymes are valued as calf rennet substitutes in the cheese industry. Rennet, a microbial coagulant, can be obtained from Mucor species isolated from cow dung. The aim of this work was to extract milk-clotting enzyme from Mucor species by submerged fermentation and to produce cheese. Among the physico-chemical parameters tested, the best results were obtained in a medium having initial pH of 7.0 and incubated at 25oC for 5 days, using glucose and peptone as carbon and nitrogen sources respectively. A partial purified extract of the enzyme was obtained by fractional precipitation with (NH4)2SO4 and its maximum activity were obtained at pH 5.5 and 550C. The clotting activity of the purified enzyme was stimulated with increasing CaCl2 concentration up to 0.05%.The enzyme was completely inactivated by heating for 5 min at 70oC. This enzyme was stable at pH 4.5–6 and below 45 °C, and this was convenient for storage and transportation. The result showed that the enzyme from Mucor was a promising microorganism for industrial milk-clotting enzyme production in Ethiopia.