"Biofuel is an alternative energy source that has drawn much attention. Microbes that can utilize various types of carbon sources are considered as potential biofuel producers. Umbelopsis isabellina, a fungal strain that consumes sugars in a corn hydrolysate in the presence of inhibitors, showed excellent potential for biofuel production in our previous study. However, some disadvantages in this energy production process still exist, such as costly nitrogen sources for fungal culture and the lack of an efficient lipid extraction method. To address these problems, this study has developed two processes that could make large scale production using this strain more feasible. First, in order to further reduce the substrate cost, algal biomass was added to a corn stover hydrolysis process to eliminate the cost of the yeast extract used for fungal culture. The addition of the algal biomass had the same effect as the addition of yeast extract on biomass accumulation and lipid yield after hydrolysis. The algal hydrolysate could also be prepared separately and used for fungal culture. In addition to reducing the substrate cost of the fungal culture, this process also provides another use for the algal biomass, which could help to further shrink the cost of the algae-based biofuel. After fungal biomass accumulation, lipid extraction is another critical step in biofuel production. The traditional Bligh & Dyer method, which uses a highly toxic and dangerous solvent system (methanol and chloroform) was considered the best method for fungal lipid extraction. Instead of using that solvent system, the less toxic solvent hexane was selected in this study as an alternative, and a three-stage lipid extraction method for the fungus Umbelopsis isabellina was developed. When applied to 1 g of biomass, this method extracted the same amount of lipids as the Bligh & Dyer method, and the lipid profile was similar."--Page ii.
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