Boosting concurrent yeast oil production and secretion by Rhodosporidium toruloides through non-ionic surfactant addition and gene expression monitoring

Abstract

Yeast oil (YO) secretion derived from glycerol was facilitated by non-ionic surfactant-enhanced conditions, leading to extracellular yeast oil formation and expression of the ACC and DGA genes. The kinetic parameters of oleaginous yeast cultivation were estimated by employing through mathematical modeling. Seven yeast strains were cultivated on a glycerol-based oil production medium. Rhodosporidium toruloides TISTR 5186 demonstrated the highest efficacy in YO production and was chosen to investigate the impact of non-ionic surfactant supplementation on releasing intracellular YO into the extracellular space. Adding Triton X-100, Tween 20, and Brij 58 induced the release of YO by R. toruloides. Highest total YO formation and oil content were observed at 4.00 ± 0.07 g/L and 78.38 ± 0.37% (w/w) for 0.7% (w/v) Tween 20, respectively. Under this condition, the expression of the ACC and DGA genes was significantly increased by 3.4 and 3.6-fold, respectively compared to the control treatment. The YO fatty acids were consistently dominated by C16:0 and C18:1 under different yeast strains and cultural conditions. Modulation of YO secretion by non-ionic surfactants is a simple technique for enhancing oil recovery without the need for cell digestion. This strategy is a promising and straightforward process that can be employed for simultaneous oil production and recovery.