产纤维素酶的金橙黄微杆菌YT9分离鉴定及其培养条件优化

Isolation, Identification and Culture Characteristics of Cellulase-producing Exiguobacterium sp.YT9

从渤海近海土壤中分离1株产纤维素酶菌株,经形态、生理生化指标和16S rDNA分析鉴定为金橙黄微杆菌。对该产酶菌株进行碳源、氮源、金属盐、培养温度、pH值和诱导物质量浓度的优化,确定最佳培养基组分和条件为:果糖20g/L、羧甲基纤维素钠(CMC)0.5g/L、蛋白胨8g/L、硫酸亚铁铵2g/L、K2HPO42g/L、NaH2PO42g/L、MnSO41g/L、pH6.5、培养温度30℃、接种量4%。优化后纤维素酶系中以羧甲基纤维素酶活力为最高,为226.27U/mL,其次是β-葡萄糖苷酶和微晶纤维素酶。

Strain YT9 with high-yield cellulase was screened from coastal soil samples, and the morphological, physiological and biochemical characteristics as well as 16S rDNA sequence homology of the selected strain were studied. Finally, the strain was identified as Exiguobacterium sp. Meanwhile, medium composition and culture conditions for cellulase production were optimized. The optimal medium for higher production of cellulase consisted of 20 g/L glucose, 0.5 g/L CMC, 8 g/L tryptone, 2 g/L ferrous alum, 2 g/L K2HPO4, 2 g/L NaH2PO4, and 1 g/L MnSO4. The maximum activity of CMCase was 226.27 U/mL at pH 6.5, 30 ℃ and 4% inoculum. At the same time, the activities of cellobiohydrolase and β-glucosidase were lower than the endoglucanase activity.