Bosire Erick M, Blank Lars M, Rosenbaum Miriam A
Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany.
Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
Appl Environ Microbiol. 2016 Jul 29;82(16):5026-38. doi: 10.1128/AEM.01342-16. Print 2016 Aug 15.
Pseudomonas aeruginosa is an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions of P. aeruginosa with fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency of P. aeruginosa in mediated current production is strongly dependent on the strain of P. aeruginosa We compared levels of phenazine production by the previously investigated model strain P. aeruginosa PA14, the alternative model strain P. aeruginosa PAO1, and the BES isolate Pseudomonas sp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm(-2) with ∼150 μg ml(-1) phenazine carboxylic acid as a redox mediator). Surprisingly, P. aeruginosa PAO1 showed very low phenazine production and electrochemical activity under all tested conditions.
Microbial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example, Pseudomonas aeruginosa might enable an entire microbial community to access a solid electrode as an alternative electron acceptor. To better understand the ecological relationships between mediator producers and mediator utilizers, we here present a comparison of the phenazine-dependent electroactivities of three Pseudomonas strains. This work forms the foundation for more complex coculture investigations of mediated electron transfer in microbial fuel cells.
铜绿假单胞菌是微生物生物电化学系统(BES)微生物群落中的重要且活跃的成员,它能产生多种吩嗪氧化还原介质。对一株模式菌株进行的纯培养实验揭示了铜绿假单胞菌与发酵微生物之间的协同相互作用,这种协同作用是通过共享的发酵产物2,3 - 丁二醇介导的。我们在此的工作表明,铜绿假单胞菌在介导电流产生中的行为和效率强烈依赖于铜绿假单胞菌的菌株。我们比较了先前研究的模式菌株铜绿假单胞菌PA14、替代模式菌株铜绿假单胞菌PAO1以及BES分离株假单胞菌属菌株KRP1以葡萄糖、发酵产物2,3 - 丁二醇和乙醇作为碳底物时的吩嗪产生水平。我们发现这三种菌株在底物依赖性吩嗪产生以及由此产生的阳极电流方面存在显著差异,BES分离株KRP1总体上是最佳的电流产生者,并且以葡萄糖作为底物时表现出最高的电化学活性(以约150μg/ml吩嗪羧酸作为氧化还原介质时为19μA/cm²)。令人惊讶的是,在所有测试条件下,铜绿假单胞菌PAO1的吩嗪产生和电化学活性都非常低。
微生物燃料电池和其他微生物生物电化学系统在废水处理和生物修复等环境技术方面具有巨大潜力。虽然人们非常重视开发实现此类系统的材料和装置,但对其潜在的微生物学和生态学的研究及深入理解却滞后了。生理学研究主要集中在纯培养系统中表现出直接电子转移的微生物。与此同时,通过例如铜绿假单胞菌产生的天然氧化还原化合物进行的介导电子转移可能使整个微生物群落能够将固体电极作为替代电子受体。为了更好地理解介质产生者和介质利用者之间的生态关系,我们在此比较了三种假单胞菌菌株的吩嗪依赖性电活性。这项工作为微生物燃料电池中介导电子转移的更复杂共培养研究奠定了基础。