Biodegradation mechanism of cellulose, hemicellulose, and lignin in bacteria-dominant aerobic composting from agricultural biomass waste:A review

The conversion of abundantly produced agricultural waste has been the bottleneck and research hotspot in the development of the agricultural economy. Composting has been a sustainable treatment method for agricultural-sourced waste, in which aerobic fermentation promotes the decomposition of organic matter into stable humus and provides nutrients for plants. Due to the complex interactions among cellulose , hemicellulose , and lignin, the degradation of biomass during composting remains challenging. The aerobic fermentation relies on the interaction of various enzymes , which gradually cleavaged macromolecules into micromolecules or oligomers through a series of oxidation and hydrolysis processes, concurrently providing the nutrients needed for microbial growth , ultimately degrading lignocellulose . Generally speaking, the degradation efficiency of lignocellulose by fungi is higher than that by bacteria. However, fungi are sensitive to temperature, have poor adaptability to extreme environments, and have a long composting cycle. Therefore, this review mainly summarizes aerobic composting dominated by bacteria and clarifies the biodegradation mechanism of lignocellulose, viz., the multi-scale understanding of the degradation mechanism of lignocellulose. The dominant bacteria (e.g., Bacillus , Pseudomonas , Rhodococcus, Enterobacter , Paenibacillus , Acinetobacter , Xantomonas, Aeromonas , and Pseudomonas ) and actinomycetes (e.g., Micromonospora , Thermomonospora , Nocardia , and Streptomyces ) can be employed to develop efficient bacterial agents that consequently increase the degradation rate of lignocellulose and promote the harmless, resource utilization, and high-value utilization of agricultural waste.