Lipid production from lignocellulosic biomass via a newly isolated oleaginous fungal strain

Microbial lipids can be an attractive feedstock for biodiesel production to replace the current plant-oil based biodiesel. Oleaginous fungi have significant advantages, such as high growth rate and high oil production, easy harvest, good tolerance on growth conditions (e.g., inhibitors, pH), and can be easily grown and controlled in bioreactors. Several oleaginous yeast and fungal strains are capable of accumulating high amount of lipids inside cells, but rarely can directly utilize lignocellulosic biomass as substrates since the lack of cellulase producing capability. A newly isolated Fusarium strain from the endophytic fungi of soybean plants was firstly discovered to generate high content of lipids (53.6-57.8% of dry biomass) and also a significant amount of cellulase enzyme compared to well-studied oleaginous strain Mortierella isabellina. This research focus on the growth behavior and characteristics of this new strain and the developing of different bioconversion processes utilizing lignocellulosic biomass for improved microbial lipid accumulation. The strain showed good carbon source utilization since it can produce a significant amount of lipids on most of carbon sources including glucose, xylose, mannose, galactose, glycerol, lactose, fructose, sucrose, cellobiose, starch, xylan, and cellulose. The strain cultivation (growth medium, temperature, agitation, light effect, etc.) was optimized and the extracellular cellulase production of this strain was enhanced by directed evolution. Investigation on the effect of pretreatment and cellulase enzyme were conducted to to achieve higher efficiency of converting lignocellulosic biomass to lipids.