Proton motive force generation from stored polymers for the uptake of acetate under anaerobic conditions

Authors


  • Present address: Aaron M. Saunders, Danish Technological Institute, Kongsvang Allé 29, Aarhus C, 8000, Denmark.

  • Editor: Anthony George

Correspondence: Linda L. Blackall, Advanced Wastewater Management Centre, The University of Queensland, St Lucia 4072, Qld, Australia. Tel.: +61 7 3365 4645; fax: +61 7 3365 4726; e-mail:blackall@awmc.uq.edu.au

Abstract

The bacteria facilitating enhanced biological phosphorus removal gain a selective advantage from intracellularly stored polymer-driven substrate uptake under anaerobic conditions during sequential anaerobic : aerobic cycling. Mechanisms for these unusual membrane transport processes were proposed and experimentally validated using selective inhibitors and highly-enriched cultures of a polyphosphate-accumulating organism, Accumulibacter, and a glycogen-accumulating organism, Competibacter. Acetate uptake by both Accumulibacter and Competibacter was driven by a proton motive force (PMF). Stored polymers were used to generate the PMF –Accumulibacter used phosphate efflux through the Pit transporter, while Competibacter generated a PMF by proton efflux through the ATPase and fumarate reductase in the reductive TCA cycle.

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