Converting lignocellulosic materials to microbial lipids is a promising approach to produce drop-in biodiesel fuel. Oleaginous filamentous fungi were used as oil producer to accumulate lipid from treated lignocellulosic materials. Mortierella isabellina was used as the model strain to accumulate lipid through several kinds of conversion processes. Soybean hull and corn stover were used as lignocellulosic materials. M. isabellina can form the pellets well in liquid part of corn stover after diluted acid pretreatment by 2 fold dilution. High solid loading ratio of soybean hull during simultaneous saccharification and fermentation process provided high lipid production. This is an abstract of a paper presented at the 2011 AIChE Annual Meeting (Minneapolis, MN 10/16-21/2011).