Engineering and biocatalytic properties of lipases and esterases prodeced by Geobacillus bacteria ; Geobacillus genties bakterijų sintetinamų lipazių ir esterazių inžinerija ir biokatalizinių savybių įvertinimas

Lipases and esterases produced by Geobacillus bacteria is a promising and important area in basic research and industrial applications. In this work the significance of Asp371, Phe375 and Tyr376 from C- terminal region for the efficient functionality of Geobacillus sp. 95 lipase (GD-95) was showen for the first time and new carboxylesterase (GDEst-95) produced by Geobacillus sp. 95 strain with a molecular size of 55 kDa was identified. In further experiments GDEst-95 esterase together with GD-95 lipase were used for the construction of the first fused lipolytic chimeric biocatalyst GDEst-lip. Because of their physicochemical and kinetic properties GDEst-95 esterase and fused GDEst-lip enzyme have a high potential for application in various industrial areas. This work also demonstrated that identical domain fusion strategy (GDLip-lip and GDEst-est) is useful for creating of new biocatalysts. It was shown that usage of several fused domains can modulate the activity and physicochemical characteristics of target enzymes for industrial applications. In this study three new Geobacillus lipases were also identified. These proteins expanded the existing information about physicochemical properties of Geobacillus lipases. Furthermore, genes of Geobacillus lipases were subjected to DNA shuffling and epPCR experiments to create more thermostable and more thermoactive lipolytic enzymes.