Development of Microbial Fuel Cell Prototypes for Examination of the Temporal and Spatial Response of Anodic Bacterial Communities in Marine Sediments.

摘要

Many bacteria can convert chemical energy to electrical energy: they oxidize diverse organic substrates, transfer electrons to anodic electrodes and thus generate electricity in microbial fuel cells (MFCs). In the marine environment, microbial fuel cells, termed either sediment or benthic microbial fuel cells, have been developed to generate power via anodic bacteria in the ocean sediment. Power is dependent upon enriched anodic bacteria that transport their electrons onto the anode. The marine deployed MFC systems can provide renewable, harvested power to trickle charge batteries or other storage devices. Through power management systems these storage devices can power traditional electronic loads of interest. The systems have the promise to allow for long term deployment of in-water sensor and communications systems, providing decreased maintenance and increased operational capabilities. In this study, two sediment microbial fuel cells were deployed in the San Diego Bay over a 60 day time period. The fuel cells deployed in the field for the purpose of sampling bacteria on and adjacent to graphite sheet anodes buried in marine sediment. The anodes were connected electrically via a potentiostat to a carbon fiber brush cathode, which floated freely in the water column. Succession and spatial response of anodic bacterial population structures were monitored. The anodes were buried in the marine sediment containing an organic carbon content of approximately 1.4% TOC. Sediment cores (1 cm x 5 cm) were extracted on each side of two parallel anode electrodes, in the space between the electrodes (approximatley 2.5 cm away from anode), and 15 cm away from the anode. Sediment cores were individually homogenized and 0.5 g per sample of the sediment was used to determine most probable number (MPN) of iron-reducing bacteria; another 0.5 g per sample of sediment was used for molecular biology analysis of DGGE (denaturing gradient gel electrophoresis) and cloning (data analysis in process).