Novel approach for the direct transesterification of fresh microalgal cells via micro-reactor

Transesterification is prevalent in the fatty acid (FA) analysis of lipids, as well as in biodiesel preparation. However, it is very inefficient to obtain the FA composition from microalgal biomass via traditional transesterification. Therefore, to satisfy the demand for rapid FA analysis in microalgal research and to simplify the microalgal biodiesel production process, we developed an approach for the direct transesterification of fresh microalgal cells by overcoming the bottlenecks of mass transfer and the solid-liquid homogeneity of transesterification in a micro-reactor with polyethylene glycol as a suspension agent. This direct transesterification takes only 10 min, and the minimum amount of fresh microalgal cells required for accurate FA analysis was reduced to a few milligrams. This new approach allows near real-time microalgal FA measurement in microorganism-related research and represents significant progress in improving the competitiveness and the possibility of the practical application of microalgal biodiesel, since drying and lipid extraction are avoided.