From waste to value: microbial valorization of low-cost renewable resources for hyaluronic acid production

The escalating global waste crisis necessitates innovative valorization strategies, and this review addresses the potential of microbial bioconversion to transform low-cost renewable wastes from industries like beverage, agriculture, and oil processing into high-value hyaluronic acid (HA). Traditionally constrained by expensive synthetic media, HA production can benefit from sustainable alternatives such as molasses, cheese whey, and palm kernel cake (PKC), which serve as efficient nutrient sources for Streptococcus zooepidemicus and genetically engineered heterogenous strains, achieving comparable yields. This study offers an overview of the latest developments, contrasting the application of natural renewable by-products and synthetic media for microbial HA synthesis in both laboratory and industrial contexts. This review highlights the limitations associated with renewable by-products and proposes strategies to maximize their utilization, contributing to a circular economy. Genetic engineering, fermentation optimization, and purification methods refining have been developed for enhanced efficiency, reduced costs, and to address by-product heterogeneity, all as part of integrated strategies to maximize the benefits from renewable by-products. This review also analyses the techno-economic viability and scalability of these processes, along with their Technology Readiness Levels (TRLs). We propose a prioritized roadmap for future R&D, which primarily focuses on improving bioconversion efficiency and metabolic capacity of microbial strains to increase HA yield from low-cost materials. Further research is crucial to optimize these processes and expand the range of suitable by-products for economically viable and sustainable HA production.