曲霉型豆豉用高产蛋白酶菌种的选育

从曲霉型阳江豆豉曲中筛选出5株菌落形态不同的曲霉(Aspergillus spp.),通过纯种发酵制备豆豉曲,测定了豆豉曲中碱性蛋白酶和中性蛋白酶的活性,从中筛选出1株蛋白酶活性较高的菌种,并对该曲霉进行ITS r DNA序列分析,发现该曲霉与Aspergillus oryzae strain P6B2(JX429926)的同源性最高,故鉴定为米曲霉(Aspergillus oryzae).以该米曲霉为出发菌株,通过紫外线诱变和硫酸二乙酯化学复合诱变处理,选育得到优良高产蛋白酶活性的突变株,其中性蛋白酶酶

Breeding of high protease-producing strain from Aspergillus of koji-making Douchi type

A higher protease-producing strain was selected within 5 different strains of Aspergillus spp. isolated from Aspergillus of koji-making Douchi type of Yangjiang by testing the alkaline and neutral protease activity with the purebred fermentation of koji-making Douehi. The strain was most highly homologous with Aspergillus oryzae strain P6B2 （JX429926） and identified as Aspergillus oryzae. With the Aspergillus oryzae as a start strain, an excellent mutant strain was mutated multiply by UV and diethyl sulfate through separation, purification and cultivation. Its neutral protease activity was 258 U/g, which was increased by 22.9% compared to that of the original strain （210 U/g） , with stable hereditary character.