Authors: Jan B A Arends Jonas Speeckaert Evelyne Blondeel Jo De Vrieze Pascal Boeckx Willy Verstraete Korneel Rabaey Nico Boon
Publish Date: 2013/11/08
Volume: 98, Issue: 7, Pages: 3205-3217
Abstract
Methane CH4 release from wetlands is an important source of greenhouse gas emissions Gas exchange occurs mainly through the aerenchyma of plants and production of greenhouse gases is heavily dependent on rhizosphere biogeochemical conditions ie substrate availability and redox potential It is hypothesized that by introducing a biocatalyzed anode electrode in the rhizosphere of wetland plants a competition for carbon and electrons can be invoked between electrical currentgenerating bacteria and methanogenic Archaea The anode electrode is part of a bioelectrochemical system BES capable of harvesting electrical current from microbial metabolism In this work the anode of a BES was introduced in the rhizosphere of rice plants Oryza sativa and the impact on methane emissions was monitored Microbial current generation was able to outcompete methanogenic processes when the bulk matrix contained low concentrations of organic carbon provided that the electrical circuit with the effective electroactive microorganisms was in place When interrupting the electrical circuit or supplying an excess of organic carbon methanogenic metabolism was able to outcompete current generating metabolism The qPCR results showed hydrogenotrophic methanogens were the most abundant methanogenic group present while mixotrophic or acetoclastic methanogens were hardly detected in the bulk rhizosphere or on the electrodes Competition for electron donor and acceptor were likely the main drivers to lower methane emissions Overall electrical current generation with BESs is an interesting option to control CH4 emissions from wetlands but needs to be applied in combination with other mitigation strategies to be successful and feasible in practiceJA was funded by the European Community’s Seventh Framework Programme FP7/20072013 under grant agreement no 226532 WV is supported by a Ghent University Multidisciplinary Research Partnership Biotechnology for a sustainable economy 01 MRA 510W The authors thank Jan Vermeulen for assistance with trace gas analysis Simon Decorte Joachim Desloover and Giovanny Ganendra are acknowledged for their fruitful discussions on the manuscript
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