Global warming and the exhaustion of fossil fuels are major world-wide problems.Thus,the production of biodiesel using various materials,such as plants,microalgae,and animal fat,has been attempted as an alternative energy source.In particular,biodiesel has two main advantages,the mitigation of carbon dioxide and as a substitute for petroleum.Microalgae also have certain advantages compared to other energy crops,including a high growth rate,short growth time,high biomass production,and low land use.The key processes involved in biodiesel production using microalgae are cultivation,harvest,lipid extraction and the transesterification of the lipids.In order to extract lipids from algal biomass,organic solvents such as hexane and a mixture of chloroform and methanol are typically used.However,the health,security,and regulatory problems associated with the use of organic solvents should be addressed.In addition,efficient solvent recovery processes are needed to commercialize these processes.Therefore,several groups have reported the use of supercritical CO2,less toxic solvent mixtures,and ionic liquids (ILs) to replace toxic organic solvents.Ionic liquids (ILs) composed entirely of ions are liquid at room temperature.Since they have negligible vapor pressure,non-flammability,and tunable physiochemical properties for a particular application which term them as “designer solvents”,ILs have recently gained much attention as alternatives for organic solvents in many processes.In particular,ILs have been used to extract protein from aqueous two phase systems,extract hormones from urine samples,and be used as alternative solvents for liquid–liquid extraction.Therefore,the direct extraction of lipid from microalgae using ILs is demonstrated in this study.