传统酿造酱油酱醪中的霉菌筛选及其部分酶系特征分析

Screening of Molds in Traditional Soy Sauce Moromi and Analysis of Some Enzymatic Characteristics

传统酿造酱油发酵过程中,微生物种类繁多,多数为环境中自然落入并参与发酵,本研究旨在从传统酿造酱醪中筛选不同的霉菌并探究其酶活力特性。本研究从酱醪中分离到49株霉菌,挑选形态有差异的18株霉菌进行分子生物学鉴定,鉴定结果归属于4个菌属,即青霉属、枝孢霉属、曲霉属和链格孢菌。对这些霉菌进行酶系分析,结果表明霉菌的酶系特点与霉菌类型密切相关,其中黑曲霉的酸性蛋白酶和β-葡萄糖苷酶突出,米曲霉、红绶曲霉和链格孢菌中性蛋白酶、糖化酶和氨肽酶活力突出。根据酶活及菌种特性,选用黑曲霉AN1和AN2分别与米曲霉进行混合制曲,发现黑曲霉AN2和米曲霉混合制曲效果更佳,相比于米曲霉大曲,其中性蛋白酶与酸性蛋白酶分别提高了42.84%和22.27%,且糖化酶和氨肽酶提高117.54%和15.10%,具有较好的应用价值,该研究为筛选酱醪中优质的霉菌提供理论依据。

There are many types of microorganisms(most of which naturally occurring in the environment)participating in the fermentation of traditional soy sauce.The aim of this study was to isolate different molds from the traditional soy sauce moromi and examine their enzymatic activities.Forty-nine mold strains were isolated from moromi,among which 18 cultured mold strains with different morphologies were selected for molecular biological identification.The results revealed four genera,including Aspergillus,Penicillium,Cladosporium and Alternaria.Analysis of enzymes in these molds showed that the enzymatic characteristics were closely related to the mold species.Among which,the acid protease andβ-glucosidase of Aspergillus niger(A.niger)were prominent,while neutral protease,glucoamylase and aminopeptidase of Aspergillus oryzae(A.oryzae),Aspergillus nomius and Alternaria alternate were prominent.According to enzymatic activity and strain characteristics,A.niger(AN1)and A.niger(AN2)were chosen to co-cultivate respectively with commercial A.oryzae to make mixed koji.It was found that the effect of the mixed koji with A.niger AN2 and A.oryzae was better.Compared with pure A.oryzae koji,the activities of neutral protease and acid protease in mixed koji increased by 42.84%and 22.27%,respectively,and the activities of glucoamylase and aminopeptidase also increased by 17.54%and 15.10%,respectively,indicating a high application potential.This study provides a theoretical basis for screening high-quality mold from moromi.