Usage of GD-95 and GD-66 lipases as fusion partners leading to improved chimeric enzyme LipGD95-GD66.

ABSTRACT

Lipases are used as biocatalysts in industrial processes mainly because of their stability at broad temperature and pH range, resistance to organic solvents and wide spectrum of substrates. The usage of several lipolytic domains, each with different activity and resistance profiles, enables both the flexibility and efficiency of industrial processes. In this study, GD-95 and GD-66 lipases produced by Geobacillus sp. 95 and Geobacillus sp. 66, respectively, were used as fusion partners to create a new fused lipolytic enzyme LipGD95-GD66. Chimeric LipGD95-GD66 lipase displayed tenfold increase in activity (200 U/mg) compared to parental GD-66 lipase, improved Vmax (10 µmol/min mg-1) and catalytic efficiency (2 ∗ 105 min-1 mM-1) for p-NP palmitate as a substrate and increased activity at 70-75 °C compared to both parental lipases. All three lipases also retained >50% of their lipolytic activity after incubation with methanol, n-hexane, ethanol and DMF for longer than three weeks, highlighting a great prospect for application in industrial processes. Moreover, transesterification results revealed the capability of parental GD-95 lipase to be the most promising biocatalyst for production of methyl and ethyl esters through eco-friendly transesterification using argan oil and ethanol/methanol as acceptors of acyl group.