To enhance the protease production and decrease cost, corn flour and soy peptone were screened as cheap raw materials for the production of extracellular proteases by Bacillus strains. Their compositions in the medium...To enhance the protease production and decrease cost, corn flour and soy peptone were screened as cheap raw materials for the production of extracellular proteases by Bacillus strains. Their compositions in the medium suitable for enzyme production of Bacillus sp. B001 were optimized using statistical experiment designs. Under the optimized conditions, the protease production of Bacillus sp. B001 was stable at the stationary stage and reached to 63,200 U/mL, approximately 1.84-fold increase compared with that using the original medium. These improvements could be attributed to the release of the catabolite repression by crude materials corn flour and soy peptone which contained low level of available nutrients. Additionally, a highly pure protease which displayed excellent stability and compatibility with high salinity, commercial laundry detergents, and organic solvents, was rapidly obtained by two-step procedure involving ammonium sulphate precipitation and anion exchange from the fermentation cultures of B001 in the optimized medium. When the culture method applied to other Bacillus strains, their protease yields were all remarkably increased approximately 2.9 to 8.5 folds. In conclusion, a low-cost, easy-purified, and effective producing strategy using the cheap raw materials was developed here, representing a potential application for protease production in various Industrial processes.展开更多
从大曲中分离到一株在酸性条件下降解生玉米淀粉能力较强的菌株AspergillusMS-09。该菌产生的生淀粉糖化酶在pH3.6的条件下对生玉米淀粉有较好的分解作用,可达到其最适pH条件下酶活的95%以上。通过对AspergillusMS-09菌的形态和18S rDN...从大曲中分离到一株在酸性条件下降解生玉米淀粉能力较强的菌株AspergillusMS-09。该菌产生的生淀粉糖化酶在pH3.6的条件下对生玉米淀粉有较好的分解作用,可达到其最适pH条件下酶活的95%以上。通过对AspergillusMS-09菌的形态和18S rDNA分析,确定该菌是一株烟曲霉。对粗酶液的性质进行初步研究发现,酶的最适作用温度为65℃,最适作用pH为4.6。进一步考察了碳源、氮源对形成耐酸生淀粉糖化酶(Acidproof Raw Starch-d igesting G lucoamylase,ARSDG)的影响,发现生玉米粉(2%,w/v)和蛋白胨(1.5%,w/v)更有利于ARSDG的形成。在最佳条件下,液体发酵酶活在pH3.6的条件下可达到80U/mL。展开更多
文摘To enhance the protease production and decrease cost, corn flour and soy peptone were screened as cheap raw materials for the production of extracellular proteases by Bacillus strains. Their compositions in the medium suitable for enzyme production of Bacillus sp. B001 were optimized using statistical experiment designs. Under the optimized conditions, the protease production of Bacillus sp. B001 was stable at the stationary stage and reached to 63,200 U/mL, approximately 1.84-fold increase compared with that using the original medium. These improvements could be attributed to the release of the catabolite repression by crude materials corn flour and soy peptone which contained low level of available nutrients. Additionally, a highly pure protease which displayed excellent stability and compatibility with high salinity, commercial laundry detergents, and organic solvents, was rapidly obtained by two-step procedure involving ammonium sulphate precipitation and anion exchange from the fermentation cultures of B001 in the optimized medium. When the culture method applied to other Bacillus strains, their protease yields were all remarkably increased approximately 2.9 to 8.5 folds. In conclusion, a low-cost, easy-purified, and effective producing strategy using the cheap raw materials was developed here, representing a potential application for protease production in various Industrial processes.
文摘从大曲中分离到一株在酸性条件下降解生玉米淀粉能力较强的菌株AspergillusMS-09。该菌产生的生淀粉糖化酶在pH3.6的条件下对生玉米淀粉有较好的分解作用,可达到其最适pH条件下酶活的95%以上。通过对AspergillusMS-09菌的形态和18S rDNA分析,确定该菌是一株烟曲霉。对粗酶液的性质进行初步研究发现,酶的最适作用温度为65℃,最适作用pH为4.6。进一步考察了碳源、氮源对形成耐酸生淀粉糖化酶(Acidproof Raw Starch-d igesting G lucoamylase,ARSDG)的影响,发现生玉米粉(2%,w/v)和蛋白胨(1.5%,w/v)更有利于ARSDG的形成。在最佳条件下,液体发酵酶活在pH3.6的条件下可达到80U/mL。
