Reimagining oil recovery: Sustainable downstream processing of oleaginous yeasts for food applications

The growing global demand for oils and lipids, alongside the environmental impact of traditional oil crop cultivation, has generated significant interest in fermentation (or specifically precision fermentation) of oleaginous yeasts to produce food-grade bio-oils. While research is growing in upstream processing and innovation, downstream processing, which includes cell harvesting, disruption, oil extraction, and purification, remains underexplored. Current downstream methods are largely chemical based due to their high yields, established protocols, and operational simplicity. However, these current methods raise concerns regarding food safety and environmental sustainability. This review provides a comprehensive overview of these challenges across the various stages of downstream processing and examines their impact on process efficiency, sustainability, and scalability. The review also identifies key research gaps and proposes future research directions to advance the field and takes a whole-system approach to the sustainable production of food grade yeast oils. Furthermore, the review proposes novel research paths by analysing and drawing inspiration from oil recovery in biorefinery research. Developing efficient downstream processes for yeast-derived oils presents several challenges, including complex bio-separation steps, limited sustainable alternatives, high capital and energy requirements, scalability issues, and a lack of integrated process understanding. There are promising strategies from biorefinery research, such as innovations in solvents, novel adsorption techniques, advances in membrane technology and insitu conversion to finished products, which could be adapted (considering appropriate regulatory frameworks) to process food-grade yeast oils. The insights within this review aim to support the development of scalable, safe, and sustainable downstream processes to meet the rising demand for alternative oils.