A New Alkaliphilic Cold-Active Esterase from the Psychrophilic Marine Bacterium Rhodococcus sp.: Functional and Structural Studies and Biotechnological Potential

Abstract

The special features of cold-adapted lipolytic biocatalysts have made their use possible in several industrial applications. In fact, cold-active enzymes are known to be able to catalyze reactions at low temperatures, avoiding side reactions taking place at higher temperatures and preserving the integrity of products. A lipolytic gene was isolated from the Arctic marine bacterium Rhodococcus sp. AW25M09 and expressed in Escherichia coli as inclusion bodies. The recombinant enzyme (hereafter called RhLip) showed interesting cold-active esterase activity. The refolded purified enzyme displayed optimal activity at 30 °C and was cold-active with retention of 50% activity at 10 °C. It is worth noting that the optimal pH was 11, and the low relative activity below pH 10 revealed that RhLip was an alkaliphilic esterase. The enzyme was active toward short-chain p-nitrophenyl esters (C2-C6), displaying optimal activity with the butyrate (C4) ester. In addition, the enzyme revealed a good organic solvent and salt tolerance. These features make this an interesting enzyme for exploitation in some industrial applications.

Characterization of a cold-active and salt tolerant esterase identified by functional screening of Arctic metagenomic libraries

“…Lip3 seems to belong to the first category, having a single-helix lid (Fig. 7a , α3) and it shows a higher catalytic activity if compared to other kinetic values of esterases and lipases described in the literature [ 61 , 62 ].…”

A Novel Halotolerant Thermoalkaliphilic Esterase from Marine Bacterium Erythrobacter seohaensis SW-135

“…The data mining of bacterial genomes for the screening and identification of enzyme-encoding genes has become an effective way to hunt for novel biocatalysts such as esterases, as a result of the ongoing development of sequencing technologies. Several novel marine esterases with diverse enzymatic properties have been screened out using a genome-sequence-based approach ( Jiang et al, 2012a ; Wei et al, 2013 ; De Santi et al, 2014 , 2016b ). Likewise, with the assistance of this approach, we identified the novel esterase E69 from the marine bacteria E. seohaensis SW-135.…”

“…Moreover, since high salt concentration tends to reduce the water activity like organic solvents, esterases from marine microorganisms have potentials in industrial biocatalytic processes in the presence of organic solvents, high salinity, and low water activity environments, such as stereospecific reaction, esterification, transesterification, and polymerization reaction ( Fuciños et al, 2012 ). Recently, an increasing number of esterases with habitat-specific characteristics have been identified from marine environments or marine microorganisms, including esterases that are thermostable ( Li et al, 2015 ; Huang et al, 2016 ), cold-active ( Fu et al, 2011 ; Jiang et al, 2012b ; De Santi et al, 2014 ; Tchigvintsev et al, 2015 ), alkaliphilic ( Park et al, 2007 ; De Santi et al, 2014 ), halotolerant ( Jiang et al, 2012a ; Fang et al, 2014 ; De Santi et al, 2016a ; Zhang et al, 2017 ), or tolerant to solvents ( Zhang et al, 2014 ; Guo et al, 2016 ).…”

Bioinformatics for Marine Products: An Overview of Resources, Bottlenecks, and Perspectives

“…Prediction of protein structures is a fundamental approach to highlight conformational aspects of molecules of biotechnological interest, for example, elucidating structural features related to environmental adaptation, such as warm or cold-adapted mechanisms that confer thermostability in extremophilic enzymes [233,234], or specifying enzymatic action useful for biotechnological applications [235]. The prediction of protein structures follows two main strategies: (1) comparative approaches, based on homology modeling [236] or protein threading techniques [237,238], which predict new structures by modeling sequences from unknown structures using solved structures from homolog sequences as templates, or by recognizing common protein folds in protein sequences that lack homolog sequences; and (2) ab initio approaches [239], based on intrinsic chemical and physical characteristics of amino acid sequences rather than previously solved structures.…”