Several active microbial communities that form biogas via decomposition of cellulose and domestic food waste (DFW) were identified among 24 samples isolated from different natural and anthropogenic sources. The methane yield was 190–260 ml CH4/g from microbial communities grown on cellulose substrates, office paper, and cardboard at 37°C without preprocessing. Under mesophilic conditions, bioconversion of paper waste yields biogas with a methane content from 47 to 63%; however, the rate of biogas production was 1.5–2.0 times lower than under thermophilic conditions. When microbial communities were grown on DFW under thermophilic conditions, the most stable and effective of them produced 230–353 ml CH4/g, and the methane content in biogas was 54–58%. These results demonstrates the significance of our studies for the development of a technology for the biotransformation of paper waste into biogas and for the need of selection of microbial communities to improve the efficiency of the process.