Cellulosic biomass consists of mainly cellulose,hemicellulose and lignin.Biodiesel is an excellent liquid fuel currently being produced from vegetable oil,a feedstock that will be unsuitable for large-scale production due to land resource limitation.Microbial lipids,especially produced by oleaginous yeasts,consist of triacylglycerols with fatty acid compositional profiles similar to those of vegetable oils.Technically,biodiesel may be made from cellulosic biomass via three consecutive processes,1)Hydrolysis of biomass to monomeric sugars; 2)Lipid production with oleaginous yeasts; and 3)Transesterification of microbial lipids.There are several steps for each process.While we and many others have done tremendous works and achieved good targets for some of those steps,process integration has just been brought into attention recently.We have been working on process integration at different levels for the biochemical conversion of cellulosic biomass into biodiesel and beyond.For example,lipid production was realized by robust oleaginous yeasts using hexoses and pentoses simultaneously in the presence of common inhibitory compounds found in biomass hydrolysates.Processes were established to recover lipid and even make fatty acid esters directly from the culture broth without the isolation of “fatty” cells.Moreover,cellulosic biomass has been used directly according to the simultaneous saccharification and lipid production process.We also developed processes for effective recycling water and nutrients in the lipid production process,which could reduce the costs greatly.Together,our efforts have been significantly advancing microbial lipid technology and should provide intriguing insights for biorefinery.