Aerobic toluene degraders in the rhizosphere of a constructed wetland model show diurnal polyhydroxyalkanoate metabolism

Vanessa Lünsmann, Uwe Kappelmeyer, Anja Taubert, Ivonne Nijenhuis, Martin Von Bergen, Hermann J Heipieper, Jochen A. Müller, Nico Jehmlich

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

14 Citationer (Scopus)


Constructed wetlands (CWs) are successfully applied for the treatment of waters contaminated with aromatic compounds. In these systems, plants provide oxygen and root exudates to the rhizosphere and thereby stimulate microbial degradation processes. Root exudation of oxygen and organic compounds depends on photosynthetic activity and thus may show day-night fluctuations. While diurnal changes inCWeffluent composition have been observed, information on respective fluctuations of bacterial activity are scarce. We investigated microbial processes in aCWmodel system treating toluene-contaminated water which showed diurnal oscillations of oxygen concentrations using metaproteomics. Quantitative real-time PCR was applied to assess diurnal expression patterns of genes involved in aerobic and anaerobic toluene degradation. We observed stable aerobic toluene turnover by Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis was upregulated in these bacteria during the day, suggesting that they additionally feed on organic root exudates while reutilizing the stored carbon compounds during the night via the glyoxylate cycle. Although mRNA copies encoding the anaerobic enzyme benzylsuccinate synthase (bssA) were relatively abundant and increased slightly at night, the corresponding protein could not be detected in theCWmodel system. Our study provides insights into diurnal patterns of microbial processes occurring in the rhizosphere of an aquatic ecosystem.

TidsskriftApplied and Environmental Microbiology
Udgave nummer14
Sider (fra-til)4126-4132
Antal sider7
StatusUdgivet - 2016

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