Promotion Effect and Mechanism Analysis of Different Strain Pre-Treatment on Methane Conversion from Lignite

To evaluate lignite degradation efficiency and the enhancement of biogas production by different microbial treatments, lignite was pre-treated with Streptomyces viridosporus (actinomycete), Phanerochaete chrysosporium (fungus), and Pseudomonas sp. (bacterium), followed by biogasification experiments. Among the three, Phanerochaete chrysosporium exhibited the highest lignite degradation rate. All microbial treatments improved both cumulative biogas yield and methane conversion, with Phanerochaete chrysosporium again demonstrating the most significant enhancement. Ultimate analysis after degradation showed the following consistent trends across all treatments: increases in carbon, hydrogen, and nitrogen contents, and reductions in sulfur and oxygen contents. A linear correlation was observed between the H/C atomic ratio and total biogas yield. Functional group analysis revealed the greatest reductions in key functional groups with Phanerochaete chrysosporium, followed by moderate changes with Pseudomonas and Streptomyces viridosporus. Pore structure characterization indicated that all microorganisms influenced lignite porosity, particularly in mesopore and micropore regions. Increases in pore volume and connectivity were associated with improved biogas production efficiency.