Lipid production from diverse oleaginous yeasts from steam exploded corn cobs

Corn cob hydrolysate was used as substrate for growth and lipid accumulation via oleaginous yeast species. A mass based suspension of 10 g 100 g corn cob hydrolysate contained 26.0 g L glucose, 8.5 g L xylose. The inhibitor concentrations were 0.16 g L acetic acid, 1.50 g L formic acid, 0.48 g L HMF and 0.06 g L furfural. These conditions reduced the cell growth of non-adapted yeast. Successful adaptation of the tested yeasts over several generations in corn cob hydrolysate was performed. The adapted yeast Candida lipolytica produced 19.4 g 100 g -1 lipids in relation to the dry weight in 7.5 g 100 g dry matter corn cob hydrolysate in fed batch mode. The scale up was done up to a volume of 2.5 litres – here lipid accumulation up to 17.5 g 100 g was demonstrated with the quantitative GC/FID analyses. Predominantly oleic acid, palmitic acid, linoleic and palmitoleic acid were produced. This lipid spectrum is suitable for biodiesel production.