Jurassic weak & non-stick coal in Hengshan of North Shaanxi Province was pretreated by the nitric acid.Then,it was biodegraded by Phanerochaete chrysosporium. The biodegradation role of the white-rot fungus for coal is extremely significant.Orthogo- nal test demonstrate that liquefied time,liquefaction temperature and the amount of fun- gus liquids etc.are the main factors affecting the coal biodegradation rate.The best tech- nical condition of the coal biological liquefaction was got.Comparing the coal sample be- fore biodegradation with that after biodegradation,it is found that the ash of the coal resi- due after biodegradation reduces significantly,H and O contents increase,C and N con- tents decrease.The biodegradation change the coal macromolecular structure.
