Emerging biotechnological strategies advancing biological lignin valorization towards polyhydroxyalkanoates

Lignin is the largest renewable aromatic resource available for producing high-value products such as biomaterials, biofuels, and chemicals. Polyhydroxyalkanoate (PHA) is a biodegradable and biocompatible polymer synthesized by various microorganisms, offering broad application potential. Microbial conversion of ligninderived aromatics into PHA promoted both lignin valorization and PHA biosynthesis. However, lignin's recalcitrance and heterogeneity pose significant challenges for its microbial degradation and value-added utilization. This review examines the entire pathway of lignin conversion into high-value products, highlighting the advantages of microbial processes for synthesizing PHA and promoting the biological upgrading of lignin. Additionally, synthetic biology techniques and metabolic regulation strategies can further enhance microbial PHA synthesis. Overall, integrating microbial PHA synthesis with lignin bioconversion not only facilitates lignin valorization but also supports the sustainable production of PHA, making a significant contribution to the utilization and sustainable development of biomass resources.