Isolation and Characterization of a Moderately Halophilic Bacterium High-producing Esterase / 微生物学通报

A moderately halophilic bacterium strain DF-B6 capable of degrading Tween 20 was isolated from solar saltern brine by plate method.Based on the phenotype,physiological and biochemical character-istics,and the phylogenetic analysis of 16S rDNA sequence,strain DF-B6 was identified as Idiomarina.The substrate specificity test showed that the lipolytic enzyme from strain DF-B6 was an esterase,and not a li-pase.The maximum esterase activity was observed in 8% NaCl concentration at 50?C,pH 8.0.The effect of various divalent cations was studied on the activity of esterase from Idiomarina sp.DF-B6 at the concentra-tion of 10 mmol/L,Mg2+,Ca2+ and Mn2+enhanced the esterase activity,while Zn2+,Fe3+ and Cu2+ inhibited its activity.