Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Microorganisms
Research on Microbes
Database
Bibliography
Publications
Library
E-Resources
Microbiology Experts
Events
Online Submission
Access Statistics

Site Visitors

blog tracking


 
The ISME Journal
Vol. 8, 2014, Pages: 963978

Microbial population and functional dynamics associated with surface potential and carbon metabolism

Shun'ichi Ishii, Shino Suzuki, Trina M Norden-Krichmar, Tony Phan, Greg Wanger, Kenneth H Nealson, Yuji Sekiguchi, Yuri A Gorby and Orianna Bretschger

J. Craig Venter Institute, La Jolla, CA, USA.

Abstract

Microbial extracellular electron transfer (EET) to solid surfaces is an important reaction for metal reduction occurring in various anoxic environments. However, it is challenging to accurately characterize EET-active microbial communities and each member’s contribution to EET reactions because of changes in composition and concentrations of electron donors and solid-phase acceptors. Here, we used bioelectrochemical systems to systematically evaluate the synergistic effects of carbon source and surface redox potential on EET-active microbial community development, metabolic networks and overall electron transfer rates. The results indicate that faster biocatalytic rates were observed under electropositive electrode surface potential conditions, and under fatty acid-fed conditions. Temporal 16S rRNA-based microbial community analyses showed that Geobacter phylotypes were highly diverse and apparently dependent on surface potentials. The well-known electrogenic microbes affiliated with the Geobacter metallireducensclade were associated with lower surface potentials and less current generation, whereas Geobacter subsurface clades 1 and 2 were associated with higher surface potentials and greater current generation. An association was also observed between specific fermentative phylotypes and Geobacter phylotypes at specific surface potentials. When sugars were present, Tolumonas and Aeromonas phylotypes were preferentially associated with lower surface potentials, whereas Lactococcus phylotypes were found to be closely associated with Geobacter subsurface clades 1 and 2 phylotypes under higher surface potential conditions. Collectively, these results suggest that surface potentials provide a strong selective pressure, at the species and strain level, for both solid surface respirators and fermentative microbes throughout the EET-active community development.

Keywords: anode biofilm; microbial community dynamics; microbial fuel cell; per-biomass electrode reducing rate; 16S rRNA clone analysis.


 
 
Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution