Research progress of Rumen microbes utilizing lignocellulose for high-value chemical production.

Lignocellulose is the most abundant renewable carbon resource in nature. However, its structural recalcitrance, arising from the complex association of cellulose, hemicellulose, and lignin, results in high pretreatment costs and inefficient enzymatic hydrolysis, thereby limiting its high-value utilization. The rumen harbors a diverse anaerobic microbial community with efficient lignocellulose-degrading capacity, interconnected metabolic networks, and considerable functional adaptability, making the rumen microbiome a promising biological platform for lignocellulose conversion. This review systematically summarizes the mechanisms of lignocellulose degradation by rumen microorganisms, the metabolic pathways underlying value-added chemical production, and the process-, community-, and genetic-level strategies used to improve lignocellulose conversion performance. It further discusses major constraints on the development of rumen-derived bioconversion systems, including the instability of in vitro microbial communities, limited control over metabolic flux, and difficulties in process scale-up. Finally, the potential of multi-omics analyses and synthetic biology to improve community stability, metabolic controllability, and product selectivity is highlighted. This review provides theoretical and technical guidance for developing sustainable lignocellulose valorization processes based on rumen microorganisms.