Title Analysis of Microbial Communities in Aquatic Sediment Microbial Fuel Cells Injected with Glucose
Author Min Kim1, Kalu I. Ekpeghere2, Soo-Hyeon Kim2, Jae-Soo Chang2, and Sung-Cheol Koh2
Address 1Chumgshim International High School, Gapyeong 477-855, Republic of Korea, 2Department of Environmental Engineering, Korea Maritime University, Busan 606-791, Republic of Korea
Bibliography Korean Journal of Microbiology, 48(4),254-261, 2012
DOI http://dx.doi.org/10.7845/kjm.2012.061
Key Words Clostridium sp., exoelectrogenesis, fermentation, sediment microbial fuel cells (SMFC)
Abstract The purpose of this research was to optimize electric current production of sediment microbial fuel cells by injecting glucose and to investigate its impact on microbial communities involved. It was shown that injection of proper concentration of glucose could increase electric current generated from sediment microbial fuel cells. When 1,000 mg/L of glucose, as opposed to higher concentrations, was injected, electric current increased up to 3 times. This increase is mainly attributed to the mutual relationship between fermenting bacteria and exoelectrogenic bacteria. Here the organic acids generated by fermenting bacteria could be utilized by exoelectrogenic bacteria, removing feedback inhibition caused by the organic acids. When glucose was injected, the population of Clostridium increased as to ferment injected glucose. Glucose fermentation can have either a positive or negative effect on electric current generation. When exoelectrogenic bacteria may readily utilize the end-product, electric current could increase. However, when the end-product was not readily removed, then detrimental chemical reactions (pH decrease, methane generation, organic acids accumulation) occurred: exoelctrogenic bacteria population declined and non-microbial fuel cell related microorganisms prospered. By injecting a proper concentration of glucose, a mutual relationship between fermenting bacteria, such as Clostridium, and exoelectrogenic bacteria, such as Geobacter, should be fulfilled in order to increase electricity production in mixed cultures of microorganisms collected from the aquatic sediments.
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