Non-sterile fermentation for enhanced lipid production by Cutaneotrichosporon oleaginosum using bifunctional benzamide as selective antibacterial agent and unique nitrogen source.

The commercial success of micro-biodiesel is currently impeded by the high lipid production cost. Here, a novel non-sterile lipid fermentation strategy was successfully developed by using bifunctional benzamide as selective antibacterial agent and unique nitrogen source. DCW, lipid concentration, and lipid content reached 24.45 g/L, 15.85 g/L, and 64.80 % when Cutaneotrichosporon oleaginosum was cultured on 60 g/L glucose supplementing 1.5 g/L benzamide as sole nitrogen source under non-sterile condition in a 3-L bioreactor. Interestingly, the non-sterile fermentation containing high-loading of bacteria resulted in comparable lipid production with sterile fermentation. This non-sterile strategy could be expanded to inexpensive substrates including crude glycerol and cassava starch hydrolysate. The fatty acid compositions indicated lipids prepared by the non-sterile fermentation were suitable for biodiesel production. By avoiding the sterilization process, this strategy could effectively reduce energy consumption and simplify the production process, which was promising for improving the techno-economics of the lipid production technology.