Discovery a novel organic solvent tolerant esterase from Salinispora arenicola CNP193 through genome mining

An esterase gene, encoding a 325-amino-acid protein (SAestA), was mined form obligate marine actinomycete strain Salinispora arenicola CNP193 genome sequence. Phylogenetic analysis of the deduced amino acid sequence showed that the enzyme belonged to the family IV of lipolytic enzymes. The gene was cloned, expressed in Escherichia coli as a His-tagged protein, purified and characterized. The molecular weight of His-tagged SAestA is ∼38 kDa. SAestA-His6 was active in a temperature (5-40 °C) and pH range (7.0-11.0), and maximal activity was determined at pH 9.0 and 30 °C. The activity was severely inhibited by Hg2+, Cu2+, and Zn2+. In particular, this enzyme showed remarkable stability in presence of organic solvents (25%, v/v) with log P > 2.0 even after incubation for 7 days. All these characteristics suggested that SAestA may be a potential candidate for application in industrial processes in aqueous/organic media.