Effects of Lignocellulosic Biomass-Derived Hydrolysate Inhibitors on Cell Growth and Lipid Production During Microbial Fermentation of Oleaginous Microorganisms—A Review

For efficient production of microbial lipids also known as single cell oil (SCO), selection of favorable growth conditions including the substrate for maximum conversion into storage lipids is imperative. Utilization of lignocellulosic biomass for microbial oil production is a promising approach as it is renewable, sustainable, and available in abundance, with a significant quantity of fermentable sugars. Because of their intricate structure and biomolecular composition, lignocellulosic substrates exhibit high recalcitrance and demand specific pretreatments to release the fermentable sugars. However, pretreating the lignocellulosic substrate not only produces assimilable sugars but also various fermentation inhibitors that can significantly impede microbial growth and/or lipogenesis. Therefore, in this review, we discuss different inhibitors present in the lignocellulosic hydrolysates, and the impact on oleaginous microbial growth and metabolic activity, particularly concerning lipid production. Furthermore, the mode of inhibition of the various inhibitors and potential strategies to detoxify these are discussed in this review.