“Statistical Optimization of Bio Diesel Production from Waste Cooking Oil Using Pva -Alginate Immobilized Lipase Enzyme as Bio Catalyst”

Abstract

The present research work emphasis on immobilization of lipase on PVA-alginate beads, which are used for biodiesel production via transesterification. The optimization of temperature, pH, and reusability of was performed on PVA-Alginate beads. The highest enzyme activity was found at a temperature of 40°C and pH 4.00. After six consecutive cycles of using the immobilized enzyme, the residual activity was 60% of the initial activity. The immobilized beads were stored at 4°C without buffer after 6 weeks, the immobilized enzyme retained 76.62% of initial activity.. The second-order mathematical model was developed using RSM. Transesterification process parameters were optimized by using ‘Full Factorial Design’ (FFD) with free lipase and immobilized lipase. The different factors considered for optimization were methanol/oil (M/O) ratio, reaction time, the weight of the catalyst with constant temperature and agitation speed. FFD was performed for free lipase, obtained the highest yield with optimum conditions; M/O ratio 9:1, reaction time 90 minutes, and weight of the catalyst was 0.3gm. Similarly, FFD was performed with immobilized lipase with the highest yield at 6:1 M/O ratio, 3 hours reaction time, the weight of the catalyst 3gm. FTIR was performed for the PVA-Alginate beads and lipase immobilized PVA-Alginate beads From FTIR spectra, the peaks shift from 1746 cm -1 to 1742 cm -1 signified the formation of biodiesel.