一株产普鲁兰酶细菌的分离鉴定及其发酵条件优化

Isolation，Identification of A Bacterial Strain Producing Pullulanase and Optimization of its Fermentation Conditions
and Optimization of its Fermentation Conditions

摘要: 从淀粉加工厂附近土壤中筛选得到一株普鲁兰酶高产菌株,编号为Z-13,其初始酶活达到5.7 U/mL.通过对此菌株的16S rDNA比对,以及生理生化鉴定,鉴定此菌株为克雷伯氏菌(Klebsiella variicola),通过发酵条件优化,确定最佳发酵产酶条件为:玉米淀粉1.5%,蛋白胨2.0%,KH2PO40.05%,MgSO4·7H2O 0.01%.装液量为70 L/250 L,培养基最初pH为6.0,发酵温度30℃,摇床转速200 r/min,发酵时间48 h,优化后菌株产普鲁兰酶的酶活高达67.8 U/mL,是优化前菌株产普鲁兰酶活性的11.89倍

Abstract: A high -producing strain of pullulanase Z-13 was isolated from the soil near a starch-processing factory. The initial activity was 5.7 U/mL. Based on 16S rDNA sequence homology analysis, Z-13 was identified as WTBXklebsiella variicola,WTBZwith its physiological and biochemistry characters. The optimum fermentation condition for Z-13 was determined as follows: corn starch 1.5%, peptone 2.0%, KH_2PO4 0.05%, MgSO_4·7H2O 0.01%.When cultured at optimum fermenting conditions (studied as follows: the content of flask is 70 L/250 L, the inoculation quantity was 8%, cultured at pH 6.0, 30 ℃, 200 r/min for 48 hours), the activity of pullulanase produced by Z-13 reached the peak at 67.8 U/mL, which was 11.89 times as the initial activity.