THESIS
2010
xii, 79 p. : ill. ; 30 cm
Abstract
As the issue of energy shortage becomes more and more severe, alternative clean and
renewable energy source is in urgent need for the sustainable development of global
society. Fuel cells as a promising solution have primary drawback of high cost due to
using noble catalyst such as Pt. Microbial fuel cell (MFC) greatly reduces the cost by
using biocatalyst. Nevertheless, previous efforts focused on using microbial consortium
as catalyst for electrode reactions of which the actual working bacteria species is not
always isolated and identified. Meanwhile, the power generation efficiency as a result of
electron transport activity of bacteria could not reach the magnitude of application
unless the electron transport activity is understood for the actual working bacteria
species. To...[
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As the issue of energy shortage becomes more and more severe, alternative clean and
renewable energy source is in urgent need for the sustainable development of global
society. Fuel cells as a promising solution have primary drawback of high cost due to
using noble catalyst such as Pt. Microbial fuel cell (MFC) greatly reduces the cost by
using biocatalyst. Nevertheless, previous efforts focused on using microbial consortium
as catalyst for electrode reactions of which the actual working bacteria species is not
always isolated and identified. Meanwhile, the power generation efficiency as a result of
electron transport activity of bacteria could not reach the magnitude of application
unless the electron transport activity is understood for the actual working bacteria
species. To this end, we are driven to use single pure strain to study the points that could
lead to improvement of the performance of MFC. Three approaches were adopted in
this thesis: 1) System design using single chamber configuration to substitute the
traditional H-type design. The power output was significantly enhanced by reducing the
internal resistance. 2) Novel pure strains, Pseudomonas putida sp. MnB1 and Rhodobacter capsulatus were found to be able to work as biocathode without any other
added electron shuttles to accept electrons from the electrode. The power output could
rise at least 3 times compared with the abiotic growth medium control. 3) Broaden the
matching of bacteria and mediator. An artificial mediator Vitamin K
3 was used to
facilitate electron transfer from Synechocystis sp. PCC 6714 in both autotrophic and
heterotrophic condition. Unlike what was previously believed, no cytotoxicity of the
mediators to the bacterial cells was observed. Hence, the toxicity is not responsible for
the unsustainable performance. Instead, the current generation is limited by intracellular
glycogen content which is excreted to the solution. To make full use of the excreted
glucose, a self-fueling MFC was constructed by combination of Synechocystis sp. PCC
6714, Shewanella Oneidensis, with addition of VK
3 to achieve higher energy efficiency
of the system.
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