Microbial community structure and function of Nitrobenzene reduction biocathode in response to carbon source switchover
Journal
Water Research
Journal Volume
54
Pages
137-148
Date Issued
2014
Author(s)
Abstract
The stress of poised cathode potential condition and carbon source switchover for functional biocathode microbial community influences is poorly understood. Using high-throughput functional gene array (GeoChip v4.2) and Illumina 16S rRNA gene MiSeq sequencing, we investigated the phylogenetic and functional microbial community of the initial inoculum and biocathode for bioelectrochemical reduction of nitrobenzene to less toxic aniline in response to carbon source switchover (from organic glucose to inorganic bicarbonate). Selective transformation of nitrobenzene to aniline maintained in the bicarbonate fed biocathode although nitrobenzene reduction rate and aniline formation rate were significantly decreased compared to those of the glucose-fed biocathode. When the electrical circuit of the glucose-fed biocathode was disconnected, both rates of nitrobenzene reduction and of aniline formation were markedly decreased, confirming the essential role of an applied electric field for the enhancement of nitrobenzene reduction. The stress of poised cathode potential condition led to clear succession of microbial communities from the initial inoculum to biocathode and the carbon source switchover obviously changed the microbial community structure of biocathode. Most of the dominant genera were capable of reducing nitroaromatics to the corresponding aromatic amines regardless of the performance mode. Heterotrophic Enterococcus was dominant in the glucose-fed biocathode while autotrophic Paracoccus and Variovorax were dominant in the bicarbonate-fed biocathode. Relatively higher intensity of diverse multi-heme cytochrome c (putatively involved in electrons transfer) and carbon fixation genes was observed in the biocarbonate-fed biocathode, likely met the requirement of the energy conservation and maintained the nitrobenzene selective reduction capability after carbon source switchover. Extracellular pilin, which are important for biofilm formation and potential conductivity, had a higher gene abundance in the glucose-fed biocathode might explain the enhancement of electro-catalysis activity for nitrobenzene reduction with glucose supply. Dominant nitroaromatics-reducing or electrochemically active bacteria and diverse functional genes related to electrons transfer and nitroaromatics reduction were associated with nitrobenzene reduction efficiency of biocathode communities in response to carbon source switchover. ? 2014 Elsevier Ltd.
Subjects
Biocathode
Carbon source switchover
Function
Microbial community structure
Nitrobenzene reduction
SDGs
Other Subjects
Aniline; Carbon; Cathodes; Electric fields; Functions; Genes; Glucose; Microorganisms; RNA; Biocathodes; Bioelectrochemical reductions; Electrochemically active bacteria; Microbial communities; Microbial community structures; Potential conductivity; Selective transformation; Switchover; Nitrobenzene; aniline; aromatic amine; bicarbonate; cytochrome c; glucose; nitrobenzene; RNA 16S; benzene; biofilm; biotransformation; community response; community structure; electrode; electrokinesis; glucose; microbial activity; microbial community; organic nitrogen compound; phylogenetics; Actinobacteria; Alcaligenaceae; article; Bacteroidetes; biocathode community; biofilm; carbon fixation; carbon source; carbon source switchover; community structure; conductance; controlled study; electric field; energy conservation; Firmicutes; gene sequence; high performance liquid chromatography; inoculation; microbial community; microbial diversity; nonhuman; Paracoccus; phylogeny; priority journal; Proteobacteria; Pseudomonadaceae; reduction; Biocathode; Carbon source switchover; Function; Microbial community structure; Nitrobenzene reduction; Aniline Compounds; Autotrophic Processes; Bacteria; Base Sequence; Bioelectric Energy Sources; Biofilms; Carbon; Carbon Cycle; Cluster Analysis; Cytochrome P-450 Enzyme System; Electric Conductivity; Electrodes; Electrons; Fimbriae Proteins; Genes, Bacterial; Genetic Variation; Linear Models; Nitrobenzenes; Oxidation-Reduction; Phylogeny; Principal Component Analysis; RNA, Ribosomal, 16S
Type
journal article