Lignocellulosic (woody) biomass is the most abundant renewable organic material on Earth. There is a subset of cellulose and xylose-metabolizing yeasts, such as select Ascomycetes and Basidiomycetes, which hydrolyze lignocellulose into glucose mononers and ferment the glucose, turning this abundant resource into usable energy. Detritivourous beetles that live in low-nutrient environments dominated by cellulosic material are speculated to have symbioses with diverse gut microbiota that aid in metabolism. In this study known strains were characterized, new species were identified, and the phylogenetic relationship of fungi found in beetle guts was investigated. Two conserved yet hypervariable regions in the ribosomal RNA genes (the ITS and SSU), which are effective markers for identifying diverse fungi at the species level, were amplified. The phylogenetic relationships of these yeasts were estimated using several sequencing alignment and integrated tree building tools: 27 unknown yeast strains were putatively identified. Further analysis will provide additional strain identification. Phenotypic data was used to support preliminary identification of the unknown yeasts. This information adds to the understanding of yeast biodiversity within a unique ecological niche, and in the future some of the characterized strains from this study may improve lignocellulosic biofuel production.