Effect of Aeration Process on Lignocellulosic Degradation, Humification and Carbohydrate-Active Enzyme (CAZymes) Genes in Aerobic Composting

This study investigated the impacts of diverse aeration processes (continuous aeration vs. intermittent aeration) and aeration rates on the aerobic composting process. The key properties examined include temperature, oxygen dynamics, lignocellulose degradation, humification, and the functional potential of carbohydrate-active enzymes (CAZymes) based on metagenomic analysis. Among all the treatments, continuous aeration at a low rate (CA_1.5) attained the highest level of lignocellulose degradation by balancing the thermophilic duration and oxygen supply. Conversely, intermittent aeration (IA_3) led to superior humus stabilization, with the ratio of humic acid to fulvic acid (H/F) increasing by 118.45% in comparison to the initial level. Low total ventilation in CA_1.5 and IA_3 facilitated an increase in the abundance of glycosyl transferases (GTs) genes. Notably, intermittent aeration (IA_3) synergistically augmented the activities of glycoside hydrolases (GHs) and GTs, propelling the efficient conversion of lignocellulose into stable humic substances. In conclusion, the aeration process influenced the functional potential of microbial CAZymes, thus exerting an influence on both the composting efficiency and the quality of the final product.