The electron transfer system of syntrophically grown Desulfovibrio vulgaris

Journal Article · Fri May 01 04:00:00 EDT 2009 · Journal of Bacteriology

DOI:https://doi.org/10.1128/JB.00356-09· OSTI ID:966126

Walker, C B; He, Z; Yang, Z K; He, Q; Zhou, J; Voordouw, G; Wall, J D; Arkin, A P; Hazen, T C; Stolyar, S; Stahl, D A

Interspecies hydrogen transfer between organisms producing and consuming hydrogen promotes the decomposition of organic matter in most anoxic environments. Although syntrophic couplings between hydrogen producers and consumers are a major feature of the carbon cycle, mechanisms for energy recovery at the extremely low free energies of reactions typical of these anaerobic communities have not been established. In this study, comparative transcriptional analysis of a model sulfate-reducing microbe, Desulfovibrio vulgaris Hildenborough, suggested the use of alternative electron transfer systems dependent upon growth modality. During syntrophic growth on lactate with a hydrogenotrophic methanogen, D. vulgaris up-regulated numerous genes involved in electron transfer and energy generation when compared with sulfate-limited monocultures. In particular, genes coding for the putative membrane-bound Coo hydrogenase, two periplasmic hydrogenases (Hyd and Hyn) and the well-characterized high-molecular weight cytochrome (Hmc) were among the most highly expressed and up-regulated. Additionally, a predicted operon coding for genes involved in lactate transport and oxidation exhibited up-regulation, further suggesting an alternative pathway for electrons derived from lactate oxidation during syntrophic growth. Mutations in a subset of genes coding for Coo, Hmc, Hyd and Hyn impaired or severely limited syntrophic growth but had little affect on growth via sulfate-respiration. These results demonstrate that syntrophic growth and sulfate-respiration use largely independent energy generation pathways and imply that understanding of microbial processes sustaining nutrient cycling must consider lifestyles not captured in pure culture.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Earth Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 966126
• Report Number(s): LBNL-2246E
• Journal Information: Journal of Bacteriology, Journal Name: Journal of Bacteriology Journal Issue: 2009; ISSN JOBAAY; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
CARBON CYCLE
COMMUNITIES
CYTOCHROMES
DESULFOVIBRIO
ELECTRON TRANSFER
ELECTRONS
ENERGY RECOVERY
GENES
HYDROGEN
HYDROGEN TRANSFER
HYDROGENASES
LACTATES
MUTATIONS
NUTRIENTS
ORGANIC MATTER
OXIDATION