霉豆瓣中优势微生物蛋白酶活性测定

Determination of protease activity of dominant microorganism from moldy bean

选择市售的2种霉豆瓣为研究对象,分离出其中的微生物,通过回接发酵实验,筛选出能发酵霉豆瓣的优势菌株M1、M2和M3。经鉴定M1为黑曲霉(Aspergillus niger)、M2为米曲霉(Aspergillus oryzae)、M3为雅致放射毛霉(Actinomucor elegant)。对优势菌株进行蛋白酶活力及氨基酸态氮含量测定。结果表明,米曲霉的中性蛋白酶和碱性蛋白酶活力最高,分别为632 U/g和416 U/g。黑曲霉产酸性蛋白酶活力及氨基酸态氮能力远高于米曲霉和毛霉,酸性蛋白酶高达872 U/g,氨基酸态氮含量高达0.997 5 g/100 g。而毛霉产的3种蛋白酶活力均在中间值,可起到一定的补充作用。

Selecting 2 kinds of moldy bean commercially available as the research objects to isolate the microorganisms, according to the tieback fermentation experiment, the dominant strains M1 （Aspergillus niger） , M2 （Aspergillus oryzae）, and M3 （Actinomucor elegant） were screened out. Then protease activity and amino acid nitrogen content of excellent strains were determined. Results showed that Aspergillus oryzae had the highest activity of neutral and alkaline protease, which was 632 and 416 U/g respectively. Acidic protease activity and amino acid nitrogen content in Aspergillus niger were much higher than those in Aspergillus oryzae and Actinomucor elegant, which were 872 U/g and 0.997 5g/100g, respectively. And Actinomucor elegant had balanced ability to produce these 3 proteases, which could play a supplementary role.