Ligninocellulosic materials are among the Earth's most abundant renewable resources. Recently the National Resources Defense Council and the Union of Concerned Scientists in a joint statement said that ligninocellulosic fermentative bioproducts have the potential to substantially reduce our consumption of gasoline. One of the best strategies to address these concerns is to develop effective microbial digestion systems. In the present study we present the culturable cellulose- and sawdust-degrading mesophilic and thermophilic microbial diversity present in the soil samples of the deep subsurface of mine (which is currently being into a Deep Underground Science and Engineering Laboratory – DUSEL) collected from the 4800 feet level. The main findings were 1) a total of 23 different operational taxonomic units (OTUs) were identified using 97% similarity cut off in 16S rDNA library; 2) Majority of the OTUs were related to phylum Firmicutes and formed sister lineages with known species belonging to order Bacillales and Clostridiales; 3) Few of the OTUs were very distantly related to known bacteria and might represent novel lineages; 4) Thermophilic and mesophilic microorganisms are present in the deep subsurface of DUSEL; and 5) These microorganisms can use cellulose and sawdust as sole sources of carbon. None of these results has been previously reported for DUSEL soil. Overall, the present work revealed the presence of different bacterial lineages in the unique environment of the deep subsurface of mine. The results also have strong implications for industrial applications of biological conversion of agriculture wastes to commodity chemicals.