MICROBIAL 16S RDNA DIVERSITY IN AN ANAEROBIC DIGESTER

The bacterial community structure of a fluidized bed reactor fed by vi nasses was analysed by molecular identification. After PCR amplificati on,three 16S rDNA clone libraries of Bacteria, Archaea, and Procarya p opulations were established. Community structure was determined by phy logenetic analysis of 556 partial rDNA sequences (about 500 bp long). 139 OTUs (Operational Taxonomic Unit) were found among which 133 and 6 were from the Bacteria and Archaea domains respectively. The majority of bacterial OTUs are not closely related to all other hitherto-deter mined sequences. The ratio Archaea/Bacteria is 1/4 and the most freque nt bacterial OTU represents less than 5% of the characterised bacteria l population. (C) 1997 IAWQ. Published by Elsevier Science Ltd.