Insight into biodiesel synthesis using biocatalyst designed through lipase immobilization onto waste derived microporous carbonaceous support

Abstract

The enzymatic conversion of vegetable oils is a cleaner alternative to the chemically catalysed transesterification processes. The present study describes the development of heterogeneous enzyme catalyst by immobilising lipase onto waste derived activated carbon (AC) support and its application in enzymatic transesterification. The study includes optimisation of enzymatic transesterification using indigenously prepared biocatalyst by considering four parameters. The main parameters affecting the biodiesel yield were recognized by statistical analysis using analysis of variance (ANOVA) and contribution factor. The obtained optimised conditions for maximum biodiesel yield were: catalyst loading 3 wt%, M/O ratio 6:1, time 5 h and temperature 20 °C. The ANOVA revealed that catalyst loading and temperature are the two most dominant parameters affecting the biodiesel yield significantly with contribution factor 68.99 and 27.95% respectively. The produced rubber seed oil methyl esters (RSOME) were characterised for estimating fuel properties and found to be comparable with conventional diesel. The catalyst is reused at the optimised condition and observed that 6–7% decay in catalytic activity after 7 cycles. Thus, AC supported lipase as a biocatalyst is highly effective in conversion of rubber seed oil (RSO) to biodiesel at optimised conditions derived using Taguchi approach.