Laboratório de Bioquímica e Microbiologia Aplicada, Instituto de Biociências Letras e Ciências Exatas, Universidade Estadual Paulista , São José do Rio Preto , Brasil.
Braz J Microbiol. 2008 Jan;39(1):108-14. doi: 10.1590/S1517-838220080001000024. Epub 2008 Mar 1.
Glucoamylase is widely used in the food industry to produce high glucose syrup, and also in fermentation processes for production beer and ethanol. In this work the productivity of the glucoamylase of Aspergillus awamori expressed by the yeast Saccharomyces cerevisiae, produced in submerged fermentation using different starches, was evaluated and characterized physico-chemically. The enzyme presented high specific activity, 13.8 U/mgprotein or 2.9 U/mgbiomass, after 48 h of fermentation using soluble starch as substrate. Glucoamylase presented optimum activity at temperature of 55°C, and, in the substratum absence, the thermostability was for 1h at 50°C. The optimum pH of activity was pH 3.5 - 4.0 and the pH stability between 5.0 and 7.0. The half life at 65°C was at 30.2 min, and the thermal energy of denaturation was 234.3 KJ mol(-1). The hydrolysis of different substrate showed the enzyme's preference for the substrate with a larger polymerization degree. The gelatinized corn starch was the substratum most susceptible to the enzymatic action.
糖化酶广泛应用于食品工业生产高葡萄糖浆，也应用于啤酒和乙醇发酵过程。在这项工作中，利用不同的淀粉，通过酵母发酵生产出的米曲酶糖化酶的生产力，通过分批补料发酵进行了评估和物理化学特性分析。利用可溶性淀粉作为底物，发酵 48 小时后，酶表现出很高的比活性，为 13.8 U/mg 蛋白质或 2.9 U/mg 生物质。糖化酶的最适温度为 55°C，在没有基质的情况下，在 50°C 下热稳定性为 1 小时。最适 pH 值为 3.5-4.0，pH 值稳定性在 5.0-7.0 之间。在 65°C 时的半衰期为 30.2 分钟，变性热能为 234.3 KJ mol(-1)。对不同底物的水解表明，该酶优先作用于聚合度较大的底物。糊化玉米淀粉是最易受酶作用的底物。
