米曲霉葡萄糖代谢抑制菌株的选育及发酵性能研究

Protoplast Mutation Breeding of Aspergillus oryzae Strain with Glucose Metablic Inhibition and its Fermentation Properties

选择对2-脱氧葡萄糖(2-DG)抗性较强的米曲霉A2.104为出发菌株,通过原生质体诱变育种,进一步获得了葡萄糖代谢抑制突变株A2.104-166。小试规模的酱油酿造实验结果显示:A2.104-166的蛋白酶和谷氨酰胺酶等主要酶系的活力均有不同程度的提升,碳水化合物消耗量下降33%,全糖/全氮、谷氨酸态氮/全氮、游离氨基态氮/全氮均有明显优势;感官鉴评结果表明A2.104-166菌株的酱油咸味弱,甜味和鲜味加强。

Aspergillus oryzae A2.104 was used as the original strain for its stronger 2-DG r6sistance. A2.104-166 was obtained as glucose metabolic inhibition mutant by protoplast mutation breeding. A bench-scale soy sauce brewing experiment showed that both protease and glutaminase activities of the swain A2.104-166 improved and carbohydrate consumption decreased by 33%. The ratios of total sugar to total nitrogen, glutamate nitrogen to nitrogen and free amino nitrogen to total nitrogen of the souce fermented by the mutant were higher than those by the original swain. Sensory evaluation results showed that the soy sauce brewed by A2.104-166 had lighter salty taste but stronger sweet and umami tastes.