米曲霉种内原生质体融合选育优良菌株

Breeding Aspergillus oryzae strain by intraspecific protoplast fusion

米曲霉HL和L5是来自酱油酿造企业的生产菌株。HL的生长速度快,而L5的中性蛋白酶活力高。以HL和L5为亲本,进行原生质体融合,筛选得到一株融合株R6。融合株比亲本株生长速度更快,孢子成熟时间快3h,中性蛋白酶活力分别比2株亲本菌株提高25.6%和19.9%,酱醅氨基氮值也比亲本菌株提高8%和5.6%。

Two Aspergillus oryzae strains （HL and L5） were often used in soy sauce brewing. HL strain grows fast while L5 strain had a high neutral protease activity. By using protoplast fusion technique, a fusion strain of R6 was obtained which grows faster and had a short period of spore maturation （3h） when using HL and L5 as parental strains. The neutral protease activity of R6 was increased by 25.6% and 19.9% compared to those of ilL and L5 strain, respectively. Amino nitrogen value of sauce mash was increased by 8% and 5.6% compared to those of ilL and L5 strain, respectively.