Biodepolymerization of some of the lower rank Indian coals by Pleurotus djamor, Pleurotus citrinopileatus and Aspergillus species were studied in a batch system. The main disadvantage in burning low rank coals is the low calorific values. To get the maximum benefit from the low rank coals, the non fuel uses of coals needs to be explored. The liquefaction of coals is the preliminary processes for such approaches. The present study is undertaken specifically to investigate the optimization of bio depolymerization of neyveli lignite by P. djmor. The pH of the media reached a constant value of about 7.8 by microbial action. The effect of different carbon and nitrogen sources and influence of chelators and metal ions on depolymerization of lignite were also studied. Lignite was solubilized by P. djamor only to a limited extent without the addition of carbon and nitrogen sources. Sucrose was the best suitable carbon source for coal depolymerization by P. djamor and sodium nitrated followed by urea was the best nitrogen source. The Chelators like salicylic acid, TEA and metal ions Mg 2? , Fe 3? , Ca 2? , Cu 2? , Mn 2? has enhanced the lignite solubilization process. The finding of the study showed that, compared to sub-bituminous and bituminous coal, the lignite has higher rate of solubilization activity.