Characterization of bacterial population during composting of municipal solid waste

Composting is a natural biological process that degrades organic matter which is carried out spontaneously by aerobic microorganisms, whose metabolic action leads to the mineralization and partial humification of organic residue. The aim of this study was to investigate survival of potentially pathogenic bacterial species throughout the process and detection of enterotoxigenic Escherichia coli (ETEC) in the compost using PCR. The presence of heterotrophic bacteria, total total and fecal coliforms, and bacteria succession were also de detrermined. Out of the total 222 bacterial colonies isolated, 33 different genera and 56 different species were identified, being Bacillus, Escherichia, Enterobacter, and Pseudomonas, the prevailing genera. Total coliform counts ranged between 9.0 x 104 and 3.0 x 106 cfu/g, and fecal coliform counts between 1.0 x 104 and 2.3 x 106 cfu/g. The composting process was partially efficient, since even though coliform counts were reduced, enterotoxigenic E. coli was detected in mature compost