Electrochemical and microbial monitoring of multi-generational electroactive biofilms formed from mangrove sediment

Caroline Rivalland, Sonia Madhkour, Paule Salvin, Florent Robert

Laboratoire des Matériaux et Molécules en Milieu Amazonien, UAG-UMR EcoFoG, 2091 route de Baduel, Campus TrouBiran, 97300 Cayenne, Guyane Française, France.

Abstract

Electroactive biofilms were formed from French Guiana mangrove sediments for the analysis of bacterial communities' composition. The electrochemical monitoring of three biofilm generations revealed that the bacterial selection occurring at the anode, supposedly leading microbial electrochemical systems (MESs) to be more efficient, was not the only parameter to be taken into account so as to get the best electrical performance (maximum current density). Indeed, first biofilm generations produced a stable current density reaching about 18 A/m² while second and third generations produced current densities of about 10 A/m². MES bacterial consortia were characterized thanks to molecular biology techniques: DGGE and MiSeq® sequencing (Illumina®). High-throughput sequencing data statistical analysis confirmed preliminary DGGE data analysis, showing strong similarities between electroactive biofilms of second and third generations, but also revealing both selection and stabilization of the biofilms.

Keywords: Dissimilarity; High-throughput sequencing; Microbial diversity; MES; Syntrophism.