A Thermostable Alkaline Lipase from a Local Isolate Bacillus subtilis EH 37: Characterization, Partial Purification, and Application in Organic Synthesis

Abstract

A mesophilic bacterial culture producing a novel thermostable alkaline lipase was isolated from oil rich soil sample and identified as Bacillus subtilis EH 37. The lipase was partially purified by ammonium sulfate precipitation and hydrophobic interaction chromatography with 17.8-fold purification and 41.9 U/ml specific activity. The partially purified enzyme exhibited maximum activity at pH 8.0 and at 60°C. It retained 100% of activity at 50°C and 60°C for 60 min. The presence of Ca +2 , Mg +2 , and Zn 2+ exhibited stimulatory effect on lipase activity, whereas Fe +3 and Co +2 reduced its activity. The enzyme retained more than 80% of its initial activity upon exposure to organic solvents, exhibited 107% and 115% activity in the presence of 15% isopropyl alcohol and 30% n-hexane, respectively. The EH 37 lipase also proved to be an efficient catalyst in synthesis of ethyl caprylate in organic solvent, thus providing a concept of application of B. subtilis lipase in non-aqueous catalysis.

Molecular cloning of a thermo-alkaliphilic lipase from Bacillus subtilis DR8806: Expression and biochemical characterization

“…The high enzyme activity at alkaline pH was probably due to Ala-Gly (first Gly-residue) substitution in the consensus sequence Gly-X-Ser-X-Gly [15]. The optimum pH of B. subtilis DR8806 lipase was identical to that of other thermophilic lipases from B. subtilis EH 37 [16], Bacillus sphaericus 205y [17], Bacillus sp. L2 [18] and a lipolytic enzyme from B. subtilis DR8806 [19].…”

Purification and biochemical characterization of an extracellular lipase from psychrotolerant Pseudomonas fluorescens KE38

“…Metal ions are responsible for the maintenance of the stability of lipases (Ahmed et al, 2010). Thus, to find out whether the different metal ions stabilize or destabilize the enzyme, the effects of Ca Figure 6.…”

Enzymatic synthesis optimization of isoamyl butyrate

“…Microbial lipases are widely diversified in their properties and substrate specificity, which make them attractive tools for industrial applications. 5 Lipases display catalytic activity towards a large variety of alcohols and acids in reactions involving ester synthesis. 6 Response surface methodology (RSM) is an efficient statistical technique for the optimization of multiple variables, in order to predict the best performance conditions with a minimum of experiments, and the optimization of the lipase-catalyzed production of various esters has been investigated by RSM .…”