Toward a circular bioeconomy: bioproduction based on Halomonas grown on non-food feedstocks

The pressing challenges of plastic pollution and fossil resource reliance drive the need for sustainable biomanufacturing using non-food feedstocks. Halomonas, an extremophile chassis for next-generation industrial biotechnology, grows rapidly in high-salt, alkaline conditions to suppress contamination, enabling robust open fermentation for bio-based polymers such as polyhydroxyalkanoates and high-value chemicals. This review focuses on two key areas: (1) native and engineered metabolic pathways in Halomonas for diverse carbon substrate assimilation; and (2) multi-layered engineering strategies for enhancing substrate utilization and stress tolerance, including metabolic flux redirection and evolutionary engineering approaches. Furthermore, we outline future directions for advancing Halomonas as an industrial chassis, such as improving its tolerance to inhibitors present in non-food feedstocks, expanding the genetic and regulatory toolkits for precise strain engineering, and diversifying its product portfolio. Collectively, these advances are critical for establishing Halomonas as a versatile and robust microbial platform for a circular bioeconomy.