角蛋白酶高产菌株的筛选鉴定及其产酶条件优化

摘要

Strains with the degradation capacity of feather keratin isolated from soils of primitive forests and nature reserve areas in Guanngxi by plate medium with feather powder as the only source of carbon and nitrogen were screened and identified, and then the enzyme-producing conditions were optimized to further enlarge source of strains with high keratinase yield and improve their enzyme-producing capacity.15 strains with the effective degradation capacity of keratin are isolated.The mycelium growth vigor of yintan 3,Tiankeng 1,Tiankeng 3,Tiankeng 4,Tiankeng 5 and Damingshan 3 strains cultured on the feather medium is good and the diameter of their mycelium zone exceeds 5 cm.Tiankeng 3 strain with the best keratin degradation capacity is identified as Trichoderma according to the morphological characteristics.The keratinase activity of Tiankeng 3 strain cultured in shake flasks under the optimum culture conditions of 20 g/L glucose,40 g/L peptone for 4 d reaches 34.20 U/mL when feather powder is used as the substrate.%为进一步扩大角蛋白酶高产菌株的来源及提高其产酶能力，采用羽毛粉为惟一碳、氮源平板培养基，对从广西几大原始森林和自然保护区的土壤中得到能够降解羽毛角蛋白的菌株进行了筛选、鉴定及其产酶条件优化。结果表明：共分离出15株可有效降解角蛋白的菌株，其中，银滩3＃、天坑1＃、天坑3＃、天坑4＃、天坑5＃和大明山3＃菌株在羽毛培养基上的菌丝长势较好，且菌丝圈直径超过5 cm，经对3株（银滩3＃、天坑3＃和大明山3＃）在羽毛培养基平板上的菌丝生长圈最大的菌株进行复筛，天坑3＃为对羽毛蛋白降解效果最好的菌株；通过对该菌株形态特征观察，初步认定其为木霉属（Trichoderma）。经优化，碳氮源分别以20 g／L 葡萄糖和40 g／L 蛋白胨为宜，该菌株在此条件下摇瓶震荡培养第4天，以羽毛粉为底物时其角蛋白酶酶活高达34．20 U／mL。