Microbiology and performance of a methanogenic biofilm reactor during the start-up period.
OBJECTIVE
To understand the interactions between anaerobic biofilm development and process performances during the start-up period of methanogenic biofilm reactor.


RESULTS
Two methanogenic inverse turbulent bed reactors have been started and monitored for 81 days. Biofilm development (adhesion, growth, population dynamic) and characteristics (biodiversity, structure) were investigated using molecular tools (PCR-SSCP, FISH-CSLM). Identification of the dominant populations, in relation to process performances and to the present knowledge of their metabolic activities, was used to propose a global scheme of the degradation routes involved. The inoculum, which determines the microbial species present in the biofilm influences bioreactor performances during the start-up period. FISH observations revealed a homogeneous distribution of the Archaea and bacterial populations inside the biofilm.


CONCLUSIONS
This study points out the link between biodiversity, functional stability and methanogenic process performances during start-up of anaerobic biofilm reactor. It shows that inoculum and substrate composition greatly influence biodiversity, physiology and structure of the biofilm.


CONCLUSIONS
The combination of molecular techniques associated to a biochemical engineering approach is useful to get relevant information on the microbiology of a methanogenic growing biofilm, in relation with the start-up of the process.
Cresson
R
R
INRA, UR50, Laboratoire de Biotechnologie de l'Environnement, Narbonne, France.
Dabert
P
P
Bernet
N
N
D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D001421:Bacteria, Anaerobic / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D019075:Electrophoresis, Capillary / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D008697:Methane / Q000378:metabolism; D019642:RNA, Archaeal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014865:Waste Disposal, Fluid / Q000379:methods
D004269:DNA, Bacterial; D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S; D008697:Methane