Direct Conversion of Wet Algal Biomass Under Supercritical Methanol Conditions

Optimization of direct liquefaction and conversion of wet algal biomass (Nannochloropsis sp.) to biodiesel under supercritical methanol conditions using response surface methodology (RSM) has been demonstrated. This one-step process allows for simultaneous extraction and transesterification of wet algal biomass. A response surface methodology (RSM) was used to analyze the influence of the three process variables, namely, the wet algae to methanol (wt/vol) ratio (1:4 to 1:12 wt/vol), the reaction temperature (240-260 ºC), and the reaction time (10-30 min) on the fatty acid methyl ester (FAMEs) conversion. The characterization of wet algal biomass was done with SEM-EDS, TEM and XRD while the analysis of algal biodiesel samples was carried out using ATR-FTIR, GC-MS and thin layer chromatography (TLC) methods. The single-step process has the potential to provide an energy efficient and economical route for algal biodiesel production.