Guangxi Key Laboratory of Subtropical Bioresource Conservation and Utilization, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, 530004 Nanning, Guangxi, People's Republic of China.
J Ind Microbiol Biotechnol. 2011 Jun;38(6):733-42. doi: 10.1007/s10295-010-0910-7. Epub 2010 Dec 1.
A newly isolated strain Penicillium sp. GXU20 produced a raw starch-degrading enzyme which showed optimum activity towards raw cassava starch at pH 4.5 and 50 °C. Maximum raw cassava starch-degrading enzyme (RCSDE) activity of 20 U/ml was achieved when GXU20 was cultivated under optimized conditions using wheat bran (3.0% w/v) and soybean meal (2.5% w/v) as carbon and nitrogen sources at pH 5.0 and 28 °C. This represented about a sixfold increment as compared with the activity obtained under basal conditions. Starch hydrolysis degree of 95% of raw cassava flour (150 g/l) was achieved after 72 h of digestion by crude RCSDE (30 U/g flour). Ethanol yield reached 53.3 g/l with fermentation efficiency of 92% after 48 h of simultaneous saccharification and fermentation of raw cassava flour at 150 g/l using the RCSDE (30 U/g flour), carried out at pH 4.0 and 40 °C. This strain and its RCSDE have potential applications in processing of raw cassava starch to ethanol.
一株新分离的青霉属菌株 GXU20 产生了一种粗淀粉降解酶，该酶在 pH4.5 和 50°C 下对生木薯淀粉表现出最佳活性。当 GXU20 在优化条件下培养时，最大的生木薯淀粉降解酶（RCSDE）活性达到 20U/ml，优化条件为使用麦麸（3.0%w/v）和豆粕（2.5%w/v）作为碳源和氮源，pH5.0 和 28°C。与基础条件下获得的活性相比，这代表了约六倍的增长。粗 RCSDE（30U/g 面粉）在 72 小时的消化过程中生木薯粉（150g/l）的淀粉水解度达到 95%。当在 pH4.0 和 40°C 下使用 RCSDE（30U/g 面粉）对 150g/l 的生木薯粉进行同时糖化和发酵时，乙醇产量达到 53.3g/l，发酵效率为 92%。该菌株及其 RCSDE 在生木薯淀粉加工成乙醇方面具有潜在的应用。
