Article

Microbial Electrosynthesis: Feeding Microbes Electricity To Convert Carbon Dioxide and Water to Multicarbon Extracellular Organic Compounds

Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA.
mBio (Impact Factor: 6.79). 06/2010; 1(2). DOI: 10.1128/mBio.00103-10
Source: PubMed

ABSTRACT

IMPORTANCE
Reducing carbon dioxide to multicarbon organic chemicals and fuels with electricity has been identified as an attractive strategy to convert solar energy that is harvested intermittently with photovoltaic technology and store it as covalent chemical bonds. The organic compounds produced can then be distributed via existing infrastructure. Nonbiological electrochemical reduction of carbon dioxide has proven problematic. The results presented here suggest that microbiological catalysts may be a robust alternative, and when coupled with photovoltaics, current-driven microbial carbon dioxide reduction represents a new form of photosynthesis that might convert solar energy to organic products more effectively than traditional biomass-based strategies.

Download full-text

Full-text

Available from: Ashley Franks, Jan 23, 2016
  • Source
    • "However, to achieve the full potential of polygeneration and successful commercial development of MES technologies, new modelling tools are desperately needed. Although there have already been a number of papers published on substrates [36] [40] and microorganisms [41] [42] and electrode material selections [17], most have focused on design point performance evaluation (or a particular experimental set up) rather than optimisation of design and operations and modelling for systematic integration with industrial flowsheets and scale-up. Systems modelling combined with thermodynamic correlations can be a valuable tool to Fig. 2. Microbial fuel cell (MFC) generates electricity by electron harvesting from waste streams using bacteria; protons transfer from the anode to cathode and reduce oxygen to produce water; the overall operation is exogenic. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite some success with microbial fuel cells and microbial electrolysis cells in recovering resources from wastes, challenges with their scale and yield need to be resolved. Waste streams from biorefineries e.g. bioethanol and biodiesel plants and wastewaters are plausible substrates for microbial electrosynthesis (MES). MES integration can help biorefineries achieving the full polygeneration potentials, i.e. recovery of metals turning apparently pollutants from biorefineries into resources, production of biofuels and chemicals from reuse of CO2 and clean water. Symbiotic integration between the two systems can attain an economic and environmental upside of the overall system. We envision that electrochemical technologies and waste biorefineries can be integrated for increased efficiency and competitiveness with stillage released from the latter process used in the former as feedstock and energy resource recovered from the former used in the latter. Such symbiotic integration can avoid loss of material and energy from waste streams, thereby increasing the overall efficiency, economics and environmental performance that would serve towards delivering the common goals from both the systems. We present an insightful overview of the sources of organic wastes from biorefineries for integration with MES, anodic and cathodic substrates and biocatalysts. In addition, a generic and effective reaction and thermodynamic modelling framework for the MES has been given for the first time. The model is able to predict multi-component physico-chemical behaviour, technical feasibility and best configuration and conditions of the MES for resource recovery from waste streams.
    Full-text · Article · Apr 2016 · Renewable and Sustainable Energy Reviews
  • Source
    • "The reactors were connected to a multi-potentiostat (CHI1040, Chenhua Co., Ltd., Shanghai, China) with cathodic potentials poised at − 500, −300, −100, and +250 mV, respectively. These potentials are higher than −600 mV, which avoids the production of H 2 in the system [16]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, we reported that Thiobacillus denitrificans could utilize poised electrodes directly as sole electron donors for autotrophic denitrification in bioelectrochemical systems. A potential-dependent denitrification process was observed and catalyzed by the biofilms colonizing on the electrode surface, with a maximum nitrate removal rate of 21.12 ± 1.67 mmol NO3-- N L- 1 day- 1 m- 2 at a potential of - 500 mV. The intermediate products (nitrite and N2O) suggested that denitrification was the main electron transfer pathway, and dissimilatory nitrate reduction to ammonium was not present in this process. Cyclic voltammetry revealed the acclimation potentials played an important role in the electrochemical activity of the biofilms. Electron transport inhibitors suggested the participation of complex I, II, and III in the electron transfer during the denitrification.
    Full-text · Article · Nov 2015 · Electrochemistry Communications
  • Source
    • "Initially the term microbial electrosynthesis was used exclusively for the microbial reduction of carbon dioxide with the help of electricity (Nevin et al., 2010; Rabaey and Rozendal, 2010). But the research field was quickly widened by multiple studies that follow the same approach of optimizing microbial production by electrical enhancement from other substrates than CO 2 , often referred to as electro fermentation (Kim and Kim, 1988; Emde and Schink, 1990; Shin et al., 2002; Steinbusch et al., 2009; Rabaey and Rozendal, 2010; Choi et al., 2012). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Microbial electrochemical techniques describe a variety of emerging technologies that use electrode-bacteria-interactions for biotechnology applications including the production of electricity, waste and wastewater treatment, bioremediation and production of valuable products. Central in each application is the ability of the microbial catalyst to interact with external electron acceptors and/or donors and its metabolic properties that enable the combination of electron transport and carbon metabolism. And here also lies the key challenge. A wide range of microbes has been discovered to be able to exchange electrons with solid surfaces or mediators but only a few have been studied in depth. Especially electron transfer mechanisms from cathodes towards the microbial organism are poorly understood but are essential for many applications such as microbial electrosynthesis. We analyse the different electron transport chains that nature offers for organisms such as metal respiring bacteria and acetogens, but also standard biotechnological organisms currently used in bio-production. Special focus lies on the essential connection of redox and energy metabolism, which is often ignored when studying bio-electrochemical systems. The possibility of extracellular electron exchange at different points in each organism is discussed regarding required redox potentials and effect on cellular redox and energy levels. Key compounds such as electron carriers (e.g. cytochromes, ferredoxin, quinones, flavins) are identified and analysed regarding their possible role in electrode-microbe-interactions. This work summarizes our current knowledge on electron transport processes and uses a theoretical approach to predict the impact of different modes of transfer on the energy metabolism. As such it adds an important piece of fundamental understanding of microbial electron transport possibilities to the research community and will help to optimize and advance bio-electrochemical techniques.
    Full-text · Article · May 2015 · Frontiers in Microbiology
Show more