Identification and characterization of a new esterase from a soil metagenomic library

Abstract:

[Objective] To discover novel esterase from soil microbes by metagenomic approach. [Methods] Tributyrin-containing LB agar plates were used to screen a metagenomic library and the predictive esterase gene on the positive clone was heterologously expressed for biochemical analysis. [Results] We successfully found a positive clone from a soil microbial metagenomic library that comprised of 120 000 clones by function-based screening. Then the putative esterase gene (estyn1) of this clone was heterologously expressed and its properties including optimum pH, optimal temperature, and tolerance to organic solvents and metal ions were studied. Its optimum pH was 9.0 and its optimal temperature was 56 °C. The esterase activity was enhanced in low concentration of organic solvents, especially in DMSO (dimethylsulfoxide, activity enhanced to 144% at 10% DMSO). [Conclusion] Novel enzymes could be discovered by metagenomic approach. ESTYN1, with good tolerance to organic solvents and high temperature, would be a promising enzyme for industrial production.