Overexpression of a<i>tpI</i> Encoding ATP Synthase Enhances the Electricity Production in Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) have been paid much attention due to its clean and renewable energy. In recent years, MFCs performed without addition of mediator were reported. In this research, the gene expression of atpI involved in ATP synthase of energy metabolism was compared at 3.7 and 37 mV applied voltage by reverse-transcription PCR. At high applied voltage, gene expression of atpI caused a 11.6-fold increase more than that at low applied voltage. Accordingly, overexpression vector harboring atpI gene was further constructed to demonstrate the effect of ATP synthase on the electricity production in MFC. The result showed that the current generated by E. coli harboring atpI gene can efficiently and rapidly be enhanced. The current production with atpI gene overexpression in E. coli was 3-fold higher than that of only pET15b vector at 106th h. Consequently, these results verified that electricity production can be improved via introduction of energy metabolism gene without addition of mediator. Keywords: Microbial fuel cells, atpI, gene expression,electricity