A preliminary analysis of microbial and biochemical properties of high-temperature compost.

We investigated the microbial community of a high-temperature compost process exhibiting an internal temperature exceeding 90 degrees C. The waste pile was crosscut and samples were collected from the bottom to the top of the refuse pile. PCR-denaturing gradient gel electrophoresis analysis suggested that the microbial community of the high-temperature compost is heterogeneous and differs from one locality to another. Heat-stable collagenases and amylases were extracted directly from the compost pile. Collagenases were located in the upper half of the pile, whereas amylases were detected mainly in the lower parts. Several extremely thermophilic strains were isolated at 80 degrees C; these strains were aerobes. Based on 16S rRNA sequence analysis, the isolates clustered together and represent one or two closely related species. We propose that these thermophilic isolates belong to a novel genus, Caldaterra, gen. nov.