Preliminary assessments of microalgae direct transesterification for biodiesel production

Biodiesel is a renewable fuel which can be produced from a wide range of biomasses. In recent years, the possibility to produce it from non-food feedstock such as microalgae has been proposed. It is well known that: i) microalgae may accumulate significant quantities of triglycerides; ii) they are fast-growing photosynthetic organisms capable of sequestering CO2; iii) they can be cultivated in fresh and sea water. Nevertheless the potential of biodiesel production from microalgae, the industrial development still asks investigation. The present contribution reports about recent results of a research program in Napoli on the biodiesel production from microalgae. The study carried out so far have highlighted the success with Stichococcus strains as microalgal feedstocks to produce fatty acid methyl esters (FAMEs) according to traditional processes: lipid extraction coupled with alkaline catalyzed transesterification of lipids (Olivieri et al., 2011, 2013). Results of the direct alkaline transesterification process of Stichococcus bacillaris algal strains are here presented. Tests were carried out under wide intervals of operating conditions: pre-contact time (time of contact of biomass with alkaline methanol at room temperature), catalyst concentration, methanol/biomass weight ratio, reaction temperature, reaction time, biomass water concentration. Effects of operating conditions on FAME yield were assessed.