热稳定碱性脂肪酶产生菌的筛选及发酵条件的优化

从渤海湾盐碱地被油污染的土样中分离筛选出6株产热稳定碱性脂肪酶菌株。其中菌株1-7产脂肪酶能力较强,其最高酶活为8.67U/mL。根据其16S rDNA序列分析和Biolog生理生化分析,初步鉴定为醋酸钙不动杆菌(Acinetobacter calcoaceticus)。初步酶学性质研究表明该菌所产脂肪酶具有较好的热稳定性,最适作用pH为9.0。摇瓶实验表明,该菌株最适产酶培养基为(g/L):玉米粉10,黄豆饼粉20,K_2HPO_4 1,NaNO_3 5,橄榄油10。最适产酶条件为:初始pH 8.0,培养温度37℃,培养时间29 h。接种量为2%,250 mL摇瓶装液量为30 mL。

Screening of thermostable alkaline lipase producing strain and its optimal fermentation condition

Six stains of bacterium producing thermostable alkaline lipase were isolated from the soil collected from bay of Bohai. The stain 1-7 showed high ability of producing lipase with the maximal level of 8.67 U/mL, which was identified as Acinetobacter calcoaceticus on the basis of the sequence of 16S rRNA and Biolog. The lipase showed good thermosta- bility. The optimal pH of the lipase was 9.0. The optimal medium for lipase production was obtained with the composition of （g/L） ： corn flour 10, bean flour 20, K2HPO4 1, NaNO3 5 and olive oil 20. The optimal conditions for fermentation were as follows： initial pH 8.0, the temperature 37℃, fermentation period 29 h and the shake flask capaeity of 30mL/250 mL with the germ concentration of 2 %.