Effect of white rot fungi pretreatment on methane production from anaerobic fermentation of coal

To investigate the effect of white rot fungi pretreatment on methane production from anaerobic fermentation of coal, fermentation experiments of biogas production were conducted using long flame coal. The coal samples pretreated with white rot fungi were the experimental group(EG), and original untreated coal samples were the control group(CG). The COD(chemical oxygen demand) mass concentration, activity of coenzyme F₄₂₀, and changes of coal morphology were measured using potassium dichromate method, ultraviolet spectrophotometry, and SEM, respectively. The results showed the following:The total gas production and conversion rate in the EG and CG were 2 322.00 mL and 5.10%, 1 330.20 mL and 4.70%, respectively. Moreover, the hydrolysis stage in the EG was significantly shorter than that in the CG. The COD value in the EG and CG was 32-176 mg/L and 576-609 mg/L, respectively, and the degradation of EG was more thorough. The maximum value of coenzyme F₄₂₀ in the EG and CG was 0.011 72 μmol/L and 0.007 97 μmol/L, respectively, and its activity was effected by TOC(total organic carbon) content and acid-producing bacteria. At the end of pretreatment and gas produciton, the roughness of the coal surface in the EG was stronger, the adsorption sites and adsorption capacity of microorganisms were also more high, and accompanied by the generation of bacterioflora. This test research demonstrates the advantages and adaptability of biological pretreatment with white rot fungi, which is beneficial to the industrialization utilization of biogas resources in coal.