Extracellular polyol esters of fatty acids by Rhodotorula yeast for streamlined biorefineries

Rhodotorula yeasts are known for their ability to accumulate lipids intracellularly in the form of triglycerides, but energy-intensive processes are required for their extraction. Recently, harvesting the extracellular lipid secretions of these yeasts has emerged as an alternative strategy, offering advantages such as easy downstream processing and enhanced scalability for industrial applications. Polyol esters of fatty acids (PEFAs) are a unique class of extracellular glycolipids produced primarily by Rhodotorula yeast. PEFAs can be used as a source of fatty acids to produce biofuels or marketed as biosurfactants. We review recent advances in PEFA production, structural diversity, role and functions, and the biosynthetic production pathway. Investigating PEFA synthesis and secretion pathways holds promise for maximizing extracellular lipid production using renewable substrates.