A cold-adapted esterase from psychrotrophic Pseudoalteromas sp. strain 643A

Abstract

A psychrotrophic bacterium producing a cold-adapted esterase upon growth at low temperatures was isolated from the alimentary tract of Antarctic krill Euphasia superba Dana, and classified as Pseudoalteromonas sp. strain 643A. A genomic DNA library of strain 643A was introduced into Escherichia coli TOP10F', and screening on tributyrin-containing agar plates led to the isolation of esterase gene. The esterase gene (estA, 621 bp) encoded a protein (EstA) of 207 amino acid residues with molecular mass of 23,036 Da. Analysis of the amino acid sequence of EstA suggests that it is a member of the GDSL-lipolytic enzymes family. The purification and characterization of native EstA esterase were performed. The enzyme displayed 20-50% of maximum activity at 0-20 degrees C. The optimal temperature for EstA was 35 degrees C. EstA was stable between pH 9 and 11.5. The enzyme showed activity for esters of short- to medium-chain (C(4) and C(10)) fatty acids, and exhibited no activity for long-chain fatty acid esters like that of palmitate and stearate. EstA was strongly inhibited by phenylmethylsulfonyl fluoride, 2-mercaptoethanol, dithiothreitol and glutathione. Addition of selected divalent ions e.g. Mg(2+), Co(2+) and Cu(2+) led to the reduction of enzymatic activity and the enzyme was slightly activated ( approximately 30%) by Ca(2+) ions.

Characterization of a novel hormone-sensitive lipase family esterase from Rhizomucor miehei with tertiary alcohol hydrolysis activity

“…The optimal pH of RmEstB is 7.5, which is similar to that of most other reported esterases [18,35,43], higher than that of a HSL esterase from Pyrobaculum calidifontis [4] and RmEstA from R. miehei [29], and lower than that of a HSL esterase from a soil DNA library [42] and EstK from P. mandelii [39]. Most microbial esterases exhibit narrow pH stabilities under alkaline conditions [11,38,44]. However, RmEstB in the present study also showed excellent stability across a broad range of pHs (4.5-10.1) (Fig.…”

“…[35], Pseudoalteromas sp. strain 643A [11] and a compost metagenomic library [38]. RmEstB displays a temperature optimum of 50 • C, and is unstable at temperatures above 55 • C (Fig.…”

Purification and properties of an extracellular esterase from a cold-adapted Pseudomonas mandelii

“…The aim of this study was to purify secreted lipolytic enzymes from the psychrotrophic bacterium P. mandelii JR-1. Only a few esterase genes from psychrotrophic bacteria have been purified (Suzuki et al 2003;Cieslinski et al 2007;Al Khudary et al 2010). But, to the best of our knowledge, our isolation of EstK is the first reported purification of a coldadapted esterase in its native form.…”

“…B11-1 (Suzuki et al 2003), EstA from Pseudoalteromonas sp. strain 643A (Cieslinski et al 2007), and EstO from Pseudoalteromonas arctica (Al Khudary et al 2010). Interestingly, PNPB was the preferred substrate for PsEst1, EstA, and EstO.…”

Two Step Purification of Acinetobacter sp. Lipase and Its Evaluation as a Detergent Additive at Low Temperatures

“…6 was shown to retain 40% of its activity at 4°C [26]. Recently, cold active lipase and esterase from metagenomic and bacterial sources were also reported [27,28] but reports on mesophilic microbes, with enzyme activity at lower temperatures, are relatively scarce. The lipase used in the present study retained 86.8% of activity at 10°C indicating its suitability for use at lower temperatures.…”