Consortia cultivation

Periphyton is known to be a hot spot of mercury methylation. It accumulates mercury and is at the base of the trophic chain. Microbial community involved in mercury methylation in this environment are little known and sulfate reducing bacteria are know to be involved in methyl mercury production. In this work, a new approach by consortia cultivation is used to investigated family among sulfate reducer involved in methylmercury production. A screening by the search of hgcA gene allowed to determine 36 consortia involved in mercury methylation. In situ microbial composition and consortia composition were analyzed. Desulfovibrionaceae, Desulfobulbaceae and Syntrophbacteraceae were identified in consortia. Consortia culture has therefore made it possible to obtain microbial families that are difficult to cultivate in pure strain by maintaining these bacteria by the production of substrates from other members of these consortia. The analysis of the microbial composition of the consortia allowed us to propose a model concerning the microbial interactions that can take place within this complex environment.