MS09-P03 A bioconjugate of lipase with polypyrrole–methyl anthranilate functionalized “worm-like” titanium dioxide nanocomposite as promising nanobiocatalystRecently the development of unique nanoscaffolds have gained quite an attention for the preparation of highly stable nanobiocatalysts in order to exploit them for the synthesis of novel compounds and biodiesel. Biodiesel is a key paradigm towards the development of sustainable environment in the future. We show this by the fabrication of novel polypyrrole–methyl anthranilate functionalized titanium dioxide nanomaterial and its conjugation to lipase for the synthesis of flavoured compound and potential in biodiesel synthesis. We demonstrated successful immobilization of lipase from Rhizopus oryzae on a Ppy–MA/TiO2 NM by physical adsorption and a glutaraldehyde-activated covalent coupling procedure. The catalytic efficiencies of the free and immobilized preparations were determined for the hydrolysis of p-nitrophenyl palmitate. The covalently immobilized lipase displayed a significantly higher activity yield (effectiveness factor of 0.97) in comparison with the adsorbed counterpart (effectiveness factor of 0.86). The binding of lipase to the Ppy–MA/TiO2 NM was confirmed by transmission electron microscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. TGA and DTA were performed to investigate the thermal stability of the synthesised biocatalysts. The storage stability, solvent tolerance, and reusability of the resulting nanobiocatalyst and the effect of pH and temperature on its catalytic activities were also investigated. The prepared nanobiocatalysts displayed remarkably improved activity in terms of solvent tolerance (activity recovery of 150% and 125% in acetone and isopropanol, respectively) in comparison with its free counterpart. We envisage that the covalent binding method played a profound role in enhancing the properties of the enzyme immobilized on the Ppy–MA/TiO2 NM. The immobilized lipase successfully synthesised flavour ester in solvent free media and n-hexane having 25.5% and 85.5% ester yields respectively and also holds vital potential for enzymatic biodiesel synthesis. Molecular docking results confirmed the successful conjugation of the enzyme-nanocomposite complex.
Keywords: Nanobiocatalyst, Molecular docking, Flavor synthesis