The mass production and limited recyclability of petroleum derived plastics has led to plastic wastes polluting our ecosystem for decades. Biological upcycling of plastic waste offers a sustainable solution for promoting decarbonization and reducing environmental pollution. However, direct microbial conversion of plastic wastes, particularly recalcitrant polyolefins, is inefficient. Chemical depolymerization of polyolefins can generate depolymerized plastic (DP) oil, comprising of a complex mixture of saturated, unsaturated, even, and odd hydrocarbons suitable for biological conversion. Understanding and harnessing robust metabolic capabilities of microorganisms to upcycle the hydrocarbons in DP oil, both naturally and unnaturally occurring, into high-value chemicals are limited. Here, we discover that an oleaginous yeast, Yarrowia lipolytica, undergoing short-term adaptation to DP oil robustly utilized a wide range of hydrocarbons for cell growth and production of citric acid and neutral lipids. Y. lipolytica demonstrates distinct planktonic and oil-bound phenotypes when grown on hydrocarbons with each exhibiting unique proteomes. Proteome reallocation toward energy and lipid metabolism enables robust growth of Y. lipolytica on hydrocarbons, with n-hexadecane as the preferential substrate. Current efforts on modular cell engineering of Y. lipolytica for upcycling DP oil into non-native products are presented.
