The Mechanism Underlying Enhanced Coal-to-Methane Conversion in Anaerobic Digestion With Betaine Supplementation

Anaerobic digestion (AD) of coal-to-methane technology represents a promising energy conversion method that not only reduces environmental pollution but also contributes to sustainable development. However, low methane conversion efficiency remains a major challenge. This study investigates the use of betaine, a green and environmentally friendly alkaloid, to enhance the AD process of coal. Our results demonstrate that betaine supplementation increases the relative abundance of key microbial populations, including Petrimonas, Desulfitibacter, Methanoculleus, and Methanosarcina, while also improving cell membrane permeability. Three-dimensional fluorescence characterization reveals elevated secretion of bacterial metabolites, leading to increased protein concentrations and enhanced enzymatic activity in the liquid phase. Moreover, the content of alkane compounds in the liquid phase increases, further confirming the enhanced conversion of coal to biological methane. In conclusion, betaine supplementation significantly improves coal AD efficiency, providing a novel approach to optimize coal fermentation and biological energy conversion.