Cathodic bacterial community structure applying the different co-substrates for reductive decolorization of Alizarin...

Selective enrichment of cathodic bacterial community was investigated during reductive decolorization of AYR fedding with glucose or acetate as co-substrates in biocathode. A clear distinction of phylotype structures were observed between glucose-fed and acetate-fed biocathodes. In glucose-fed biocathode, Citrobacter (29.2%), Enterococcus (14.7%) and Alkaliflexus (9.2%) were predominant, and while, in acetate-fed biocathode, Acinetobacter (17.8%) and Achromobacter (6.4%) were dominant. Some electroactive or reductive decolorization genera, like Pseudomonas, Delftia and Dechloromonas were commonly enriched. Both of the higher AYR decolorization rate (k(AYR)=0.46) and p-phenylenediamine (PPD) generation rate (k(PPD)=0.38) were obtained fed with glucose than acetate (k(AYR)=0.18; k(PPD)=0.16). The electrochemical behavior analysis represented a total resistance in glucose-fed condition was about 73.2% lower than acetate-fed condition. The different co-substrate types, resulted in alteration of structure, richness and composition of bacterial communities, which significantly impacted the performances and electrochemical behaviors during reductive decolorization of azo dyes in biocathode.