Obscure yet Promising Oleaginous Yeasts for Fuel and Chemical Production

The rapid depletion of petroleum-based fossil fuels has led to the development of alternative fuel and energy solutions from renewable resources. Lipid-derived oleochemicals and sugar-derived bioethanol were initially produced from plant feedstocks, but in the interest of agricultural land conservation and food security, the focus has now shifted toward so-called 'third-generation feedstocks', of which yeasts are a major component. The quest to identify economically lucrative bioprocesses has led to the identification of several nonconventional oleaginous yeast species that have certain advantages over existing model species. Here, we review such underexplored oleaginous yeast species and discuss their potential bioeconomy applications. We also provide a broader perspective on possible avenues for strain improvement to reduce the cost of lipid production.