Overexpression and characterization of a new organic solvent-tolerant esterase derived from soil metagenomic DNA.

In this study, an esterase, designated EstC23, was isolated from a soil metagenomic library. The protein was amenable to overexpression in Escherichia coli under control of the T7 promoter, resulting in expression of the active, soluble protein that constituted 30% of the total cell protein content. This enzyme showed optimal activity at 40 °C and retained about 50% maximal activity at 5-10 °C. EstC23 showed remarkable stability in up to 50% (v/v) benzene and alkanes (high logP solvents). When incubated for 7 days in the presence of 50% benzene or alkanes, the enzyme maintained its 2-3 fold elevated activity. The purified enzyme also cleaved sterically hindered esters of tertiary alcohols. These results indicate that EstC23 has potential for use in industrial processes.