Sophorolipid production from delignined corncob residue by Wickerhamiella domercqiae var. sophorolipid CGMCC 1576 and Cryptococcus curvatus ATCC 96219

Abstract

Delignined corncob residue hydrolysate (DCCRH) and detoxified DCCRH were used for single cell oil (SCO) and single cell protein (SCP) production of Cryptococcus curvatus ATCC 96219 and for sophorolipid (SL) production of Wickerhamiella domercqiae var. sophorolipid CGMCC 1576. Both C. curvatus and W. domercqiae could utilize glucose in DCCRH to grow and accumulate lipids or particle-shaped SLs. DCCRH detoxification by activated carbon adsorption not only improved cell growth and lipid accumulation of C. curvatus but also increased SL production and proportion of lactonic SL in total SL. A total biomass of 17.36g/l with a lipid content of 44.36% could be achieved after cultivation of C. curvatus on the detoxified DCCRH. The predominant fatty acids of the produced SCO were oleic, stearic, and palmitic acids (27.2, 20.5, and 15.7%, respectively). When W. domercqiae cells were cultivated on DCCRH and SCO, total SL production of 39.08g/l (DCCRH + SCO) and 42.06g/l (detoxified DCCRH + SCO) were obtained. Furthermore, when cell lysate of C. curvatus, oleic acid, and DCCRH/detoxified DCCRH was used as nitrogen and carbon sources, total SL production reached 37.19g/l and 48.97g/l, respectively. These results demonstrated that renewable DCCRH can be utilized for the production of high-value SCO and SLs.