Abstract

Biogas plants continuously convert biological wastes mainly into a mixture of methane, CO₂ and H₂O a conversion that is carried out by a consortium of bacteria and archaea. The microbial community structure of the fermentation process was evaluated by using oligonucleotide probes complementary to conserved sequences of the 16S rRNAs of phylogenetically defined groups of methanogens. At the beginning of fermentation, Eubacteria are the main group and the count of Archaea then constitutes only an insignificant percentage of the population of microorganisms. During the process of fermentation, we recorded a very significant increase in methanogenic microorganisms after 40 days of the process in progress. It is reflected in the quantity and the composition of released biogas.

Key words: Methane fermentation, methanogenic microorganisms, phylogenetic diversity, rRNA.