米曲霉高产蛋白酶菌株的选育及在酱油酿造中的应用研究

[目的]筛选蛋白酶活力高的菌株酿造酱油.[方法]通过对沪酿3042米曲霉进行紫外线和LiCl复合诱变, 筛选高产蛋白酶突变株,并对其遗传稳定性和产生的蛋白酶性质进行研究,同时将该突变株应用于酱油酿造试验.[结果]通过诱变得到高产蛋白酶突变株米曲霉UF366, 其蛋白酶活力达1 440 U/g,比对照提高了33.3;.UF366菌株的遗传稳定性好,在pH 7.2,40℃时其中性蛋白酶活力最高;在90℃处理30 min,蛋白酶活力完全丧失.[结论]采用UF366米曲霉发酵的酱油氨基酸态氮和全氮分别为0.637和1.14 g/100 mL,与出发菌株沪酿3042米曲霉相比分别提高了36.7;和39.0;.

A Study on Screening of High Productive Proteinase Strain of Aspergillus Oryzae and Its Application in Soy Sauce Brewing

[Objective and Method]The protoglast of Huniang 3042 Aspergillus Oryzae was compoundly treated by UV irradiation and lithium chloride for high proteinase producing mutant. The hereditary stability and proteinase property of mutant were studied.The brewing experiment of soy sauce was conducted by mutant. [Result]The results showed that the strain of UF366 Aspergillus Oryzae was obtained with high proteinase activity. The neutral proteinase activity reached 1 440 U/g and were 33.3% more than the original strain. UF366 Aspergillus Oryzae has good hereditary stability by inoculating 20 times.When pH 7.2 and 40℃ were treated,the proteinase activity of UF366 Aspergillus Oryzae were the highest.The proteinase activity lost completely when the temperature reached 90℃ in 30 minutes.[Conclusion]The result of brewing experiment was as follows, the amino acid nitrogen and total nitrogen reached 0.637 g/100 mL and 1.14 g/100 mL,were 36.7% and 39.0% more than Huniang 3042 Aspergillus Oryzae.