Pretreatment and lipid extraction from wet microalgae: Challenges, potential, and application for industrial-scale application

Abstract

The production of oil from microalgae has tremendous potential for reducing environmental problems generated using conventional fossil fuels. The present barrier for industrial-scale lipid production from algal biomass for biofuel application comes from the high extraction cost which is usually performed after drying the biomass. The lipid extraction cost can be significantly reduced if the extraction is performed directly on wet biomass. The lipid recovery from the wet biomass at the present state is very low to be competitive at large-scale application. Due to the high moisture content, a pretreatment of wet biomass is needed prior to the lipid extraction to increase the overall oil recovery. There are different pretreatments (e.g., high-pressure homogenization, ultrasound sonication, microwave irradiation, etc.) that can be used to disrupt the robust cell wall of microalgae prior to the oil extraction. Sometimes, both the pretreatment and lipid extraction can be performed using the same apparatus to reduce the overall production cost. The process economy and the cost of lipid extraction of different pretreatment methods need to be assessed carefully before considering its commercial-scale application.