Energy

Event Date: 
Wednesday, March 25, 2015 - 18:00 - 18:15
Institution: 
UTS
Title: 

Photosynthetic Microbial Fuel Cells: From Sunlight to Bioelectricity

Abstract: 

Microbial fuel cells (MFCs) harvest electricity from microorganisms capable of catalyzing the conversion of chemical energy in organic compounds into electrical power. As any other fuel cells, MFCs consist of an anode and a cathode chamber connected together by an external circuit. The flow of electrons from the anode to the cathode generates a current. A major limitation for the use of MFCs is their cost per unit of electricity as they often require expensive catalysts, ion-exchange membranes and air-pumps. This presentation describes a photosynthetic biocathode in a sediment-type microbial fuel cell (pMFC) constructed without a proton exchange membrane and exposed to sunlight. The carbon and stainless steel cathode did not contain any catalyst, but was covered in a biofilm composed of a complex community including microalgae and cyanobacteria. The impacts of various parameters, such as temperature and dissolved oxygen, on the performance of sediment-type pMFCs were monitored. We found that higher temperatures lowered the anode potential by boosting the metabolism of the anodic biofilm. The biological production of oxygen in close proximity to the illuminated cathode significantly increased its performance as compared to that achievable with mechanical aeration. However, the photosynthetic biofilms grown in this study did not appear to catalyse oxygen reduction reactions, since a clean electrode, without biofilm, performed equally well. Instead, the reduction of oxygen at the cathode during daytime is likely to follow the peroxide pathway. 

Event Date: 
Wednesday, January 29, 2014 - 18:15 - 18:30
Institution: 
Civ and Env Engineering UNSW
Title: 

Indirect electron transfer in microbial fuel cells: Role of electron shuttles

Abstract: 

The energy conversion can be realized using microbial fuel cells (MFCs) in which electrons extracted from organics are transferred to a solid electrode by electrogenic microorganisms. To make use of electrons donated by bacteria far away from the electrode, external electron transfer mediators were added to MFCs to enable the shuttles of electrons, causing a significant improvement of electron transfer efficiency and thus an increased power performance. Quinones and iron oxides are two types of electron shuttles that have been extensively studied in MFCs recently. Researchers have also employed different electrochemical approaches to explore the extracellular electron transfer mechanisms from cell to electrode mediated by these two electron shuttles. This presentation will mainly provide information about the different electron transfer mechanisms of quinones and iron oxides.

Event Date: 
Wednesday, January 25, 2012 - 18:15 - 18:30
Institution: 
UNSW
Title: 

The impact of petroleum hydrocarbons on microbial diversity in a sub-Antarctic soil; a proxy for soil health

Abstract: 

Anthropogenic sources of contamination remain a legacy throughout the Antarctic Region, with the majority of contamination occurring alongside concentrated human activities at research stations. At Macquarie Island, an Australian Sub-Antarctic territory we have been investigating the impact of petroleum hydrocarbon contamination in the form of Special Antarctic Blend (SAB) diesel fuel on the microbial ecology of sub-Antarctic soils. Whilst bioremediation strategies are currently underway on the Island, there is a lack of petroleum hydrocarbon contamination guidelines specific to Antarctic or sub-Antarctic regions. Additionally, there is insufficient site-specific toxicity data available for remediation end points to be established. Therefore, we have assessed the bacterial and fungal response to increasing concentrations of SAB diesel fuel through a combination of novel culturing methods, flow cytometric analysis of cell numbers and massively paralley pyrosequencing targeting the 16S and ITS genes. Results of this investigation will provide the scientific basis for understanding how much fuel is too much and how clean is clean enough?

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