Microalgae are producing intracytoplasmic lipid droplets, when cultured in nitrogen depleted conditions. Those lipids are a potential biofuel source. Nevertheless the cost of the lipid extration remains an obstacle to the real development of this alternative source of energy. Pretreatments have to be explored. We investigate in our group the application of electrical and/or mechanical treatments, and their effects on the membrane and wall of the micro-organism, at the level of the single cell, using therefore specific microfluidic systems.