一株高蛋白含量小球藻TX的分离鉴定及其诱变育种

【背景】小球藻由于蛋白含量高、营养丰富,在水产养殖上可直接作为鱼、虾、贝类的优质饵料。【目的】对从养殖环境中分离的小球藻进行诱变,选育生长快、蛋白含量高的突变株,为水产养殖天然饵料生产提供优良藻种资源。【方法】以从养殖环境中筛选的生长相对较快且蛋白含量较高的TX作为出发藻株,对该藻株进行分子鉴定,并对该藻株进行紫外诱变、甲基磺酸乙脂(ethyl methyl sulfonate,EMS)诱变和复合诱变,采用96孔板高通量筛选技术和递进式重复筛选方法选育高生物量、高蛋白突变株。【结果】经18SrRNA基因序列分析,TX鉴定为Chlorella sorokiniana,从540个可能的突变株中筛选到8个遗传稳定且生长较快的突变株,其中H10的总蛋白含量达64.2%,可溶性蛋白含量达0.44g/L,干重达0.72g/L,分别较出发藻株提高3.4%、15.8%和26.2%。【结论】突变株H10蛋白含量高且生长较快,可用于天然饵料生产。

Isolation, identification and mutation breeding of Chlorella sorokiniana TX with high protein content

Background] Chlorella sp. contains 20 amino acids needed for animal growth and rich in protein, polysaccharides, unsaturated fatty acids, carotenoids, astaxanthin and various vitamins. It can be used as high-quality natural bait for fish, shrimp and shellfish. Objective] Chlorella TX was isolated from cultured environment. The method of mutagenesis was used to breed high biomass and protein content mutants in order to obtain excellent algae resources for aquaculture natural bait production. Methods] Chlorella TX, a relatively fast-growing and high protein content algae, was screened from the aquaculture environment as the starting strain. 18S rRNA gene sequence analysis was employed to identify strain Chlorella TX, and then ultraviolet mutagenesis, ethyl methane sulfonate (EMS), compound mutagenesis, 96-well plate high-throughput screening and progressive repeated screening were used to breed high biomass and protein content mutants. Results] TX was identified as Chlorella sorokiniana by 18S rRNA gene sequence analysis. Eight mutants with genetic stability and growing fast were screened out from 540 mutants after progressive repeated screening. The total protein, soluble protein content and dry weight content of mutant H10 were 64.2%, 0.44 g/L and 0.72 g/L respectively, which were 3.4%, 15.8% and 26.2% higher than original algae strain TX. Conclusion] The advantageous characteristics of H10 with high protein and growing fast can be used for natural bait production.