Direct electricity production from green onion’s roots

Abstract

AbstractIn recent years, extensive scientific efforts are conducted to develop clean bio-energy technologies that have the potential to compete with the contaminating fossil fuels. Electricity production was previously generated from photosynthetic organisms in bio-photo electrochemical cells (BPECs), and microbial fuel cells (MFCs). The main approach of such methods was to exploit the ability of the organisms to perform external electron transfer (EET) to reduce the anode of an electrochemical cell. By far, these methods were applied to microorganisms, seaweeds, and plant leaves. The ability of roots to perform EET was applied in solutions that consist of molecular electron acceptors, however, it was not used for electricity production yet. In this work, we integrate green onion roots in a bio-electrochemical cell and show that it can produce continuous bias-free electric current for more than 24 h. This current is enhanced upon irradiation of light on the onion’s leaves. We apply 2D-fluorescence maps to show that NADH serves as a major electron mediator between the roots and the anode, while its concentration in the external root matrix is increased upon irradiation of the leaves. Direct electricity production from roots may be integrated with soil-based MFCs or plant leaves-based BPECs and pave the way towards the establishment of novel renewable energy technologies.