Studies on the Production of Microbial Rennet by Solid State Fermentation

用固態醱酵生産微生物凝乳的研究

M. S. Thakur ； N. G. Karanth ； Krishna Nand

《Transactions of the Mycological Society of Republic of China》 5卷1&2期 (1990/12) Pp. 13-28

https://doi.org/10.7099/TMSRC.199012.0013

摘要

導因於小牛凝乳的嚴重不足，黴菌凝乳已廣泛被接受爲小牛乳的替代品。第一次嚐試以固態醱酵培養具有潛力的高溫黴菌Mucor meihei。另一些營養方面，會影響牛乳凝結的活性生産的因素，已加以探討。從黴菌凝乳獲得的牛乳凝結酵素爲酸性蛋白酶，很近似胃蛋白酶或Chymosin。Chymosin是小牛凝乳或凝乳抽出物中，主要牛乳凝結的成份。已知，Chymosin對牛乳的K-酪蛋白的作用，乃酪餅凝結的重要步驟。從事浸漬醱酵時，發現利用固態醱酵生産凝乳較浸漬培養爲便宜。將産自浸漬醱酵和固態醱酵的凝乳，比較二者蛋白水解活性，發現從固態醱酵的凝乳其活性較低。一些營養方面，會影響牛乳凝結的活性生産的因素，已加以探討。六種複雜碳源加以測試，在小麥粉對麥麩比例爲90:10時，每克乾重醱酵麥麩可有34,000SU牛乳凝結活性。於有機或無機氮源比較時，有機氮有利於高酵素産量。所獲得最高牛乳凝結活性爲58,000SU/g。當牛乳凝結活性比蛋白水解活性的比值高時，酵素才可以比得上市場的凝酶。由此酵素醱酵所得之乳酪經風味測品評甚佳。

並列摘要

Due to acute shortage of calf rennet in recent years fungal rennets have received wide acceptability as calf rennet substitutes. A potent strain of Mucor miehei, a thermophilic fungus, was cultivated under Solid State fermentation conditions for the first time. The effect of some important nutritional parameters on the first time. the effect of some important nutritional parameters on the production of milk clotting activity was investigated. Milk clotting enzyme also known as acid protease is obtained from fungi and is similar to either pepsin or chymosin. Chymosin is the main milk clotting component of the calf rennet or rennet extract. It is known that the action of chymosin on kappa casein of milk is primarily responsible for the formation of cheese coagulation (Anstrup 1980). Studies were conducted in submerged fermentation conditions and found that rennet production on solid state fermentation was cheaper than produced in submerged fermentation. The proteolytic activity of rennet produced in submerged fermentation and solid state fermentation was also compared, and reported that rennet produced on solid state fermentation was having less proteolytic activity than the submerged grown culture. The effect of some important nutritional parameters on the production of milk clotting activity was investigated. Six complex type carbon sources were tried and wheat flour at 90:10 ratio gave a milk clotting activity of 34000 SU/g of dry moldy bran. Among the inorganicand organic nitrogen sources tried, organic sources favored higher enzyme production. The maximum milk clotting enzyme activity obtained was 58,000 su/g. The euzyme had a high ratio of milk clotting to proteolytic activity comparable to the commercial fungal rennets in the market. The cheese prepared from the enzyme was favorably evaluated in organoleptic tests.