Dual-stage biorefinery to convert spentwash hydrolysate into oleochemicals using Trichosporon cutaneum and Yarrowia lipolytica

Abstract

Yeast lipids from low-cost renewable feedstock are valuable resources for oleochemicals thus enabling circular chemistry. Current study focuses on lipid and volatile fatty acid (VFA) production through dual-stage fermentation of spentwash in a biorefinery framework with Trichosporon cutaneum (Tc) and Yarrowia lipolytica (Yl). During cell proliferation phase, Tc and Yl accumulated 2.9 and 2.5 g/L of dry biomass respectively in acid-hydrolysed spentwash (AHSW) and produced 16 and 5.5 g/L of total VFA respectively. Lipid yields (29.8%) and lipid titres (0.89 g/L) were higher in Tc/AHSW, when compared to Yl indicating the efficacy of Tc in spentwash bioremediation. Lipid accumulation was enhanced to 35% in Tc/AHSW, in presence of 0.05% NH4Cl due to oxidative stress of ammonium ions. Analysis of fatty acid composition revealed the presence of higher oleic acid, which is ideal for biodiesel production. The results demonstrate a sustainable biorefinery model for bioremediation of spentwash and its value addition.