Bioenergy production from yeast through a thermo-chemical platform

Abstract

Alternative fuels are urgently needed to mitigate greenhouse gas emissions. This study was conducted to recover bioenergy from non-edible feedstock, an oleaginous yeast biomass obtained during fed-batch cultivation of Yarrowia lipolytica. Yeast oil (lipids) was extracted from the harvested biomass and readily converted into biodiesel using the non-catalytic transesterification method. The conversion yield of the convertible lipids was 97.4 wt%, even with a high content of unidentified impurities (> 12.7 wt%). To maximize bioenergy production and minimize waste generation, the yeast biomass residue after oil extraction was used as a feedstock for pyrolysis. The yield of flammable gases (H₂, CO, and CH₄) produced from catalytic pyrolysis of residual biomass was 194.7 mmol under CO₂ conditions, a 14.3 % increase compared to that under N₂ conditions. Consequently, the use of a thermochemical platform (non-catalytic transesterification and catalytic pyrolysis under CO₂ conditions) for yeast biomass valorization enhances bioenergy production and minimizes waste generation.