The applications and challenges of polyhydroxybutyrate (PHB) as ketobiotics in food science

Polyhydroxybutyrate (PHB), as a representative member of the polyhydroxyalkanoate (PHA) family, has traditionally been regarded as an eco-friendly biomaterial due to its biodegradability and biocompatibility. In recent years, studies on gut microbiota have revealed its unique "ketone donor" property - by slowly releasing 3-hydroxybutyrate (3-HB) in the gut, it achieves precise regulation of the symbiotic interaction between the microbiota and the host, enabling it to break away from the traditional category of prebiotics and becoming the core carrier of "ketone-donor prebiotics" (i.e., "ketobiotics"). This paper systematically reviews the microbial synthesis, green extraction and purification processes, physical and chemical properties, and modification techniques of PHB. Then, it focuses on deepening the probiotic mechanism mediated by ketone donor - the collaborative regulation of "microbiota-immune-metabolism." This paper also summarizes the latest research progress of PHB in the food-related field, its potential application and current challenges as a ketobiotic in functional foods. Finally, future directions such as "ketobiotic precise intervention scheme" and "construction of human gut ketone donor - microbiota interaction map" are discussed. Hopefully, this paper will provide insights for the transformation of PHB from laboratory to food industry, and promote ketone-donor prebiotics as a strategic bridge between biomanufacturing and human health.