DOI：10.3969/j.issn.1000-9973.2025.07.017

中图分类号：TS201.3 文献标志码：A 文章编号：1000-9973（2025）07-0115-04

Study on Mutagenesis and Screening of Aspergillus oryzae Strains Used for Low-Temperature Koji Making

FENG Xia，LIAO Yun-sheng，ZHANG Bei-bei*，LI Feng，CHEN Qi-ming， ZHANG Ling-li， MA Zhuo-yuan，GAO Li-hong

（Sichuan Food Fermentation Industry Research and Design Institute Co.，Ltd.， Chengdu 611130，China）

Abstract： In this study，Aspergillus oryzae strain CM5 with good soy sauce brewing performance preserved at the Southwest Center of Industrial Culture Collection in China （SICC） is selected. Ten mutant strains with good performance are obtained through atmospheric pressure and room temperature plasma （ARTP） mutagenesis breeding. After low-temperature screning of the mutant strains， ATM12 with higher total enzyme activity and acid protease activity is selected for further research. The results show that the average spore germination rate of ATM12 koji reaches 87.64% ，indicating that the germination rate is good.There are significant diferences in colony morphology and mycelium between ATM12 and Aspergillus oryzae Huniang 3.O42，and there is no significant diference in spore morphology and size between ATM12 and Aspergillus oryzae Huniang 3.O42 in terms of microstructure. In terms of total enzyme activity，the total enzyme activity of ATM12 is lower than that of Aspergillus oryzae Huniang 3.042，but acid protease activity of ATM12 is significantly higher than that of Aspergillus oryzae Huniang 3.042，which has positive significance for high-salt liquid-state fermentation of sauce mash with acidic pH under low-temperature conditions.

Key Words： soy sauce; Aspergillus oryzae ; low-temperature koji making; ARTP mutagenesis

酱油由豆酱演变而来，从宋朝开始就出现了“酱油\"这个词，是我国的传统调味品[1]。酱油是一种以大豆、小麦或麸皮为主要原料，通过发酵制成的具有独特香气的特殊调味品，含有多种氨基酸和有机化合物[2]，根据酱油的发酵工艺主要分为低盐固态发酵和高盐稀态发酵两种[3]。其中，低盐固态发酵时间较短，导致各种风味物质的累积不够，从品质上无法与高盐稀态发酵相比[4]。但是高盐稀态发酵时间较长，对发酵条件的要求较高，导致酱油的生产成本居高不下[5]，因此对其发酵关键控制点进行研究成为该领域的研究重点。

米曲霉是酿造酱油的主要菌株，可以分泌蛋白酶、α -淀粉酶、谷氨酰胺酶、果胶酶等多种酶系[6，其中蛋白酶是酱油发酵过程中的重要酶系，可以促进原料降解，生成氨基酸、短肽、多肽等物质[7]。已有研究指出，高盐稀态发酵酱油的关键控制点是低温制曲和常温发酵[8]，米曲霉蛋白酶活力是影响酱油原料利用率和产品品质的关键因素，因此选育可以用于低温制曲的米曲霉菌株有极其重要的意义[9]。目前国内的酱油生产企业主要采用米曲霉沪酿3.042以及在此基础上优化的新菌种，虽然其生长快速，产酶系丰富，但是菌丝较长，导致制曲时出现大曲结板严重、透气性差、曲温升高过快不易控制、烧曲等问题[10-11]。基于此，该项目组结合SICC菌种储备优势，从菌种库中筛选性能较好的米曲霉菌株，通过ARTP诱变并低温筛选优良菌株，与采用米曲霉沪酿3.042进行对比，以期得到能够在低温条件下进行制曲且产酶能力强并能克服米曲霉沪酿3.042缺点的优良菌株。……