(677b) Microwave-Mediated Transesterification of Algal Biomass to Biodiesel Under Supercritical Ethanol Conditions

We demonstrated an integrated novel approach to convert lipid-rich, wet/dry algae (Nannochloropsis Salina) into fatty acid ethyl esters (FAEE) under microwave-mediated supercritical ethanol conditions. This process enables simultaneous extraction of lipids from algal biomass and convert/transesterify them into algal biodiesel in a shorter reaction of time and may reduce the energy consumption due to simplified separation and purification steps. High conversion rates can be possible when the extractive-transesterification of algal biomass was performed near-critical or supercritical conditions resulted due to ionic conduction and dipolar polarization microwave effect. Experimental runs were designed to optimize the process parameters to evaluate the effect on the algal biodiesel under controlled microwave power conditions. We described the use of passive heating elements made of silicon carbide (SiC) to aid the microwave-mediated heating process at higher temperatures. The algal biomass characterization and algal biodiesel analysis were performed using various analytical instruments such as FTIR, SEM-EDS, TEM, TLC and GC-MS. The confocal laser scanning microscopy and fluorescence spectroscopy has been implemented for the detection of algal biodiesel fuel obtained from dry and wet algal biomass. The thermogravimetric analysis (TGA) under nitrogen and oxygen environment was performed to check the thermal and oxidative stability of ethyl esters. This simple in situ transesterification process using greener solvent and catalyst-free approach can be potential route for algal biodiesel production.