Enhanced biocatalytic activity of immobilized steapsin lipase in supercritical carbon dioxide for production of biodiesel using waste cooking oil

The present work reports covalent immobilization of steapsin lipase (SL) on Immobead-350 support matrix (IMB) to make a robust biocatalytic system to work under supercritical carbon dioxide condition (Sc-CO2). The developed biocatalyst (IMB:SL) was characterized in details and utilized to convert waste cooking sunflower oil (WCSO) into value-added energy chemical (biodiesel) in Sc-CO2. All reaction process parameters were optimized in detail which offered 86.33% yield of biodiesel from WCSO. The developed Sc-CO2 protocol is compared with the solvent-free conventional synthesis, which indicates almost twofold higher yield of biodiesel in Sc-CO2 media as compared to solvent-free condition. To extend the scope, we have tested fresh and waste cooking oils (WCO) from various sources, offering 81–94% yield of biodiesel. The biocatalyst activity was investigated in various parameters of supercritical condition to know the biocatalyst stability in Sc-CO2. Besides this, IMB:SL biocatalyst was effectively reused up to five recycle.