Non-photosynthetic bacteria produce photocurrent mediated by NADH

Abstract

In recent years, the concern from the global climate change has driven an urgent need to develop clean energy technologies that do not involve combustion process that emit carbon into the atmosphere. A promising concept is microbial fuel cells that utilize bacteria as electron donors in a bio-electrochemical cell performing a direct electron transfer via conductive protein complexes or by secretion of redox active metabolites such as quinone or phenazine derivatives. In the case of photosynthetic bacteria (cyanobacteria) electrons can also be extracted from the photosynthetic pathway mediated mostly by NADH and NADPH. In this work, we show for the first time that the intact non-photosynthetic bacteria Escherichia coli can produce photocurrent that is enhanced upon addition of an exogenous electron mediator. Furthermore, we apply 2D-fluorescence measurement to show that NADH is released from the bacterial cells, which may apply as a native electron mediator in microbial fuel cells.

Bio-electricity production from Fibroblasts and their cultivation media

“…[6][7][8] that can conduct a direct electron transfer to the anode of the BEC by conductive protein complexes such as pili and metal respiratory complexes [9][10][11] . The electron transfer may also be conducted by diffusive redox species that can be released from the cells such as NADH, flavins, vitamins and phenazines 2,[12][13][14] . Rather than endogenous bioelectron mediators, the electron transfer can be enhanced by adding exogenous electron mediators such as potassium ferricyanide 15 .…”

Roots Fuel Cell Produces and Stores Clean Energy

“…10,11 The electron transfer between the exoelectrogenic bacteria and the anode may be conducted by either of two mechanisms: mediated electron transfer (MET) 6,7,12−15 or direct electron transfer (DET). 1,16,17 In the case of MET, redox-active metabolites such as derivatives of flavins, phenazines, or NADH 18 are secreted from the cells to reduce the anode. The MET can be enhanced by the addition of an exogenous electron mediator such as potassium ferricyanide.…”

“…42 The photocurrent production of such systems is about 2−3 orders of magnitude greater than for microorganismbased biophoto electrochemical cells (BPECs). 43 Interestingly, photocurrent may also be harvested from nonphotosynthetic cells and organisms such as nonphotosynthetic bacteria, 18 retinal organoids, 44 and fruits. 45 Rather than using live organisms, photoelectricity generation can be accomplished by isolating photosynthetic components at different degrees of purification, such as chloroplasts, thylakoid membranes, and photosystems 46−53 or by catalysis of isolated enzymes.…”

“…In recent years, many efforts have been made to replace fossil fuels with green energy technologies. The utilization of MFCs for electricity generation has been extensively studied for more than a hundred years. − In this method, bacteria acts as an electron donor at the anode or an electron acceptor at the cathode. , The electron transfer between the exoelectrogenic bacteria and the anode may be conducted by either of two mechanisms: mediated electron transfer (MET) ,,− or direct electron transfer (DET). ,, In the case of MET, redox-active metabolites such as derivatives of flavins, phenazines, or NADH are secreted from the cells to reduce the anode. The MET can be enhanced by the addition of an exogenous electron mediator such as potassium ferricyanide. − DET is performed by conductive pili − or metal respiratory complexes. , Among the species that perform a high degree of DET are Shewanella onedis and Geobacter.…”

“…The photocurrent production of such systems is about 2–3 orders of magnitude greater than for microorganism-based biophoto electrochemical cells (BPECs) . Interestingly, photocurrent may also be harvested from nonphotosynthetic cells and organisms such as nonphotosynthetic bacteria, retinal organoids, and fruits …”