Lipid Production by Yeast Trichosporon oleaginosus on the Enzymatic Hydrolysate of Alkaline Pretreated Corn Cobs for Biodiesel Production

Biodiesel is still mainly produced from different vegetable (e.g., rapeseed, palm, soybean, sunflower, and used cooking oils) oils and animal fats, and therefore it has a negative impact on food and feed prices. For biodiesel production as an alternative feedstock, lipids from oleaginous microorganisms could be used. One of the oleaginous microorganisms is yeast Trichosporon oleaginosus that has the capacity to grow and accumulate lipids on different lignocellulosic hydrolysates. In this study, corn cobs were pretreated by alkali at loading from 0.08 to 1.6 g/g dry weight of untreated (raw) corn cobs (g NaOH/gDW_UCC) at 121 °C for 30 min. In a further step, alkaline pretreated corn cobs were subjected to the enzymatic hydrolysis by using commercial multienzymes mixtures. The optimal alkali loading (0.16 g/gDW_UCC) was related to the highest glucose and xylose yields which were observed during enzymatic hydrolysis of substrate. In this study, T. oleaginosus was applied for lipid production on the enzymatic corn cobs hydrolysates by following bioprocess configurations: separate hydrolysis and lipid production (SHLP) and simultaneous saccharification and lipid production (SSLP). The SSLP was characterized by higher lipid yield (88.88 mg/gDW_UCC) and productivity (2.4 g/(L day)) as well as significant bioprocess time reduction. On the basis of the above-mentioned facts, it is obvious that SSLP with T. oleaginosus has great potential for application in industrial scale.