Cellulosic ethanol fermentation process will be economically viable provided both five and six carbon sugars are fermented simultaneously. At present we have major concerns using genetically modified yeast Saccharomyces Cerevisiae (424A) including slow utilization of xylose when compared to glucose and inhibition of xylose utilization pathway due to presence of inhibitors which are produced during pretreatment process. In order to have a fundamental understanding of how the xylose utilization pathway is inhibited, one has to first understand the lipid profile of the yeast in pure sugar media and lignocellulosic hydrolyzate.  Some of the experiments we will carry out in order to understand the above mentioned process include: (1) Xylose utilizing rates under different temperatures, and the corresponding differences on the lipidome level, (2) Changes of xylose utilizing rate during the process of cultivation in both pure sugar media and hydrolyzate produced by enzymatic hydrolysis of AFEX treated corn stover and the corresponding changes on lipidome level as a function of time and (3) Compare the difference in xylose utilizing dynamics and difference in lipidomes for genetically modified yeast strain 424A to that of native strain. Lipid profiling will be done using LCMS using normal and reverse phase separation.