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采用平板透明圈法的定性筛选和Folin-酚试剂定量检测筛选相结合,从罗非鱼养殖系统分离的优势菌中进行蛋白酶产生菌株的筛选,并对其进行16S rDNA细菌鉴定。结果显示,84株优势菌中共有15株蛋白酶产生菌株,其中10株具有较高的蛋白酶活力(>45.0 U/mL),分别为D45、D21、D18、D11、D55、D30、D7、D50、D51和D53,以菌株D51和D53的蛋白酶活力最强,其最高酶活力均大于70.0 U/mL。将各菌株进行16S rDNA鉴定,初步认定菌株D50、D11、D18和D21属于Bacillus sp.;菌株D45、D51和D53属于Exiguobacterium sp.;菌株D55属于Aeromonas sp.;菌株D30属于Agrobacterium sp.;菌株D7属于Pseudomonas sp.。此10株具有较高蛋白酶活力的菌株可作为水产养殖益生菌的潜在菌源,从而提高水产动物对蛋白的利用效率,减少养殖过程氮的排放。
The qualitative screening by the plate transparent circle method and Folin-phenol reagent quantitative detection and screening combined with the screening of the protease-producing strains from the predominant bacteria isolated from the tilapia culture system and the 16S rDNA bacterial identification. The results showed that there were 15 strains of protease produced by 84 strains of dominant bacteria, of which 10 strains had high protease activity (> 45.0 U / mL), which were D45, D21, D18, D11, D55, D30, D7, D50, D51 and D53, the highest protease activity of strain D51 and D53, the highest enzyme activity were greater than 70.0 U / mL. Strains D50, D11, D18 and D21 belonged to Bacillus sp .; strain D45, D51 and D53 belonged to Exiguobacterium sp .; strain D55 belonged to Aeromonas sp .; strain D30 belonged to Agrobacterium sp .; strain D7 Belongs to Pseudomonas sp. The 10 strains with higher protease activity could be used as potential bacterial source for probiotics in aquaculture, so as to improve aquatic animal’s utilization efficiency of protein and reduce nitrogen emission during aquaculture.