产低温碱性脂肪酶菌株Acinetobacter johnsonii LP28的鉴定及发酵条件优化

Identification and Optimization of Fermentation Conditions of Acinetobacter johnsonii LP28 Producing Cold-Adapted and Alkaline Lipase

从实验室保藏的49株碱性脂肪酶产生菌中筛选出产低温碱性脂肪酶菌株LP28,初步酶学性质研究表明,该脂肪酶的最适作用温度为30,℃,最适作用pH为9.0,粗酶液在室温条件下处理48,h仍具有93.78%的残余酶活.该菌经16S,rDNA鉴定为约氏不动杆菌(Acinetobacter johnsonii),同源性为99%.摇瓶实验表明,该菌株最适产酶培养基为(g/L):淀粉10,牛肉膏20,K2HPO41,PVA-大豆油20.最高酶活为3.06,U/mL.

Strain LP28 was selected from the 49 alkaline lipase producing strains preserved in laboratory. The characterization of the crude enzyme exhibited maximum activity at 30 ℃ and pH 9.0 and retained 93.78% of its maximum activity after remaining 48 h at the room temperature. The strain was identified as Acinetobacter johnsonii by 16S rDNA assay and showed 99% homology. The optimal medium for lipase production was determined as follow （g/L） ：starch 10,beef extract 20 ,K2HPO4 1 ,PVA-bean oil 20. The alkaline lipase activity reached maximal level of 3.06 U/mL.