Open Access Research article

Establishment and metabolic analysis of a model microbial community for understanding trophic and electron accepting interactions of subsurface anaerobic environments

Lance D Miller12, Jennifer J Mosher12, Amudhan Venkateswaran12, Zamin K Yang12, Anthony V Palumbo12, Tommy J Phelps12, Mircea Podar12, Christopher W Schadt12 and Martin Keller12*

Author Affiliations

1 Biosciences and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

2 Virtual Institute for Microbial Stress and Survival, LBNL One Cyclotron Road MS 977-152 Berkeley, CA 94720, USA

For all author emails, please log on.

BMC Microbiology 2010, 10:149  doi:10.1186/1471-2180-10-149

Published: 24 May 2010

Abstract

Background

Communities of microorganisms control the rates of key biogeochemical cycles, and are important for biotechnology, bioremediation, and industrial microbiological processes. For this reason, we constructed a model microbial community comprised of three species dependent on trophic interactions. The three species microbial community was comprised of Clostridium cellulolyticum, Desulfovibrio vulgaris Hildenborough, and Geobacter sulfurreducens and was grown under continuous culture conditions. Cellobiose served as the carbon and energy source for C. cellulolyticum, whereas D. vulgaris and G. sulfurreducens derived carbon and energy from the metabolic products of cellobiose fermentation and were provided with sulfate and fumarate respectively as electron acceptors.

Results

qPCR monitoring of the culture revealed C. cellulolyticum to be dominant as expected and confirmed the presence of D. vulgaris and G. sulfurreducens. Proposed metabolic modeling of carbon and electron flow of the three-species community indicated that the growth of C. cellulolyticum and D. vulgaris were electron donor limited whereas G. sulfurreducens was electron acceptor limited.

Conclusions

The results demonstrate that C. cellulolyticum, D. vulgaris, and G. sulfurreducens can be grown in coculture in a continuous culture system in which D. vulgaris and G. sulfurreducens are dependent upon the metabolic byproducts of C. cellulolyticum for nutrients. This represents a step towards developing a tractable model ecosystem comprised of members representing the functional groups of a trophic network.