Utilization of n-Hexane as Co-Solvent to Increase Biodiesel Yield on Direct Transesterification Reaction from Marine Microalgae

Direct transesterification reaction requires optimization of reaction conditions due to both the lipid extraction and lipid transesterification reactions that occur at the same place and time. Co-solvent utilization is considered as one of some ways to improve the yield in the direct transesterification reaction. In this study, transesterification was done directly on the marine microalgae biomass Nannochloropsis sp. Design variations in this research including the volume ratio of methanol: n-hexane, the molar ratio of lipid: methanol, and reaction time. From these variations, the volume ratio of methanol : n-hexane 1:1, molar ratio of lipid: methanol 1: 400, and reaction time 4 hours can increase biodiesel yield until 90.9% for Nannochloropsis sp. FAME contents were analyzed by Gas Chromatography and Mass Spectroscopy (GCMS). Saturated fatty acid content is more dominant on biodiesel reached 52.72%. (C) 2015 The Authors. Published by Elsevier Ltd.