Abstract
Mechanisms of lignite solubilization were investigated to understand the microbial succession in lignite piles along with weathering after excavation. Solubilization of lignite by phosphate buffer was significantly increased with increases in buffer pH. Chelation of iron was involved in solubilization of lignite, though it was less effective than pH increase. Reduction of iron was another important process for solubilizing lignite.
When lignite samples were incubated, greater solubilization occurred under anaerobic conditions than under aerobic conditions. Increase in pH were also an important process, especially for newly excavated lignite samples, while the reduction process was important for more weathered lignite samples. Microbial solubilization/degradation of lignite is considered to occur by complex processes cooperating at anaerobic spots and aerobic sites in lignite piles; anaerobic conditions accelerate lignite solubilization and thus solubilized lignite is utilized by microorganisms at aerobic sites.
