New alkaline lipase from Rhizomucor variabilis: Biochemical properties and stability in the presence of microbial EPS

Abstract

A new strain of Rhizomucor variabilis producing an active extracellular lipase was identified and characterized in the present studies. The culture conditions were optimized and the highest lipase production amounting to 136 U/mL was achieved after 4 days of cultivation. The optimum pH (5.5) and temperature (28 °C) were determined as the best conditions for R. variabilis lipase production. The isolated enzyme preparation exhibited maximum activity at 40 °C and pH 8.0. Lipase from R. variabilis was stable up to 50 °C during 2 H retaining 80% of its initial activity. The enzyme was highly stable in the pH range of 7.0-9.0. Moreover, the addition of naturally obtained exopolysaccharides (EPS) significantly enhanced lipase activity. The presence of EPS derived from Ganoderma applanatum and Rhizobium leguminosarum enhanced the lipase activity, which was 22% and 31%, respectively, higher than that in the control experiments. Simultaneously, the pH activity profiles remained unchanged. The Michaelis-Menten constant and the turnover number of the enzyme for p-nitrophenyl palmitate in the standard assay conditions were estimated at a level of 0.631 mM and 0.674 Sec(-1) . In conclusion, the results obtained in this work present a newly isolated lipase preparation stabilized with EPS or without modification as a very effective tool for industrial application.

Bacterial exopolysaccharides as a modern biotechnological tool for modification of fungal laccase properties and metal ion binding

“…Incubation of laccases with Rh76 EPS and Rh1021 EPS contributes to significant changes in the optimum pH of the enzymatic reaction towards more alkaline values. Similar results were obtained by Bancerz et al [10] in their study of lipases in the presence of bacterial (from R. leguminosarum bv. trifolii Rt24.2) and fungal (from Ganoderma applanatum ) polysaccharides.…”

“…The effect of polysaccharides isolated from the bacterium R. leguminosarum bv. trifolii Rt24.2 on the stability and activity of lipase isolated from Rhizomucor variabilis was analyzed with satisfactory results by Bancerz et al [10, 50]. In the present study, a positive effect of the presence of proposed polysaccharides in the reaction mixture on the stability of the laccase during 30-day incubation (especially at 25 °C) was detected.…”

“…This is one of the reasons why the presence of exopolysaccharides can modulate the native properties of enzymes and yield high stability of proteins under extreme stress conditions. EPSs of this type were used, e.g., to preserve lipase from deactivation by chemicals produced during the enzyme-catalyzed reaction [10]. …”

Characterization of a novel alkaline-stable lipase from Acinetobacter haemolyticus KV1 isolated from an oil palm mill effluent

“…Lipases catalyze hydrolysis of long chain triglycerides at the interface between the insoluble substrate and water, forming diacylglyceride, monoglyceride, glycerol and free fatty acids as products. Aside from catalyzing their natural substrates, lipases catalyze the enantio-and regioselective hydrolysis as well as synthesize a broad range of natural and non-natural esters (Bancerz et al, 2016;Batumalaie et al, 2017).…”

“…is a coccobacilliary, aerobic and Gram-negative bacterium that belong to the wider class of Gammaproteobacteria (Park et al, 2009;Anbu et al, 2011). The bacterial species is oxidase-negative, exhibiting twitching motility (Bancerz et al, 2016) and occur in pairs. Acinetobacter sp.…”