Electrochemical insights into bacterial respiration upon polarized substrates: A proposal for tricking bacteria and compelling them to exhibit desired activities

Based on similarities between bacterial respiration and electrodic processes, we here present some propositions about microbial activities in electrochemical systems, which justify why microorganisms could interact with polarized surfaces and how these interactions could potentially be utilized for bioengineering as well as life science issues. In this paper, using a potentiodynamic polarization approach, the polarity effect on the bioelectrocatalytic response of a facultative anaerobe, viz. Pseudomonas aeruginosa was scrutinized. The investigations revealed that under the anodic regime, both respiratory options (aerobic and anaerobic) are available and the positively charged electrode could provide a suitable niche for bacterial growth. Microscopic observations illustrated that under such a circumstance, it is possible to electrochemically stimulate the bacterial cells on the polarized surfaces. Under cathodic polarization, the electrode serves as electron-source, and by decreasing the system impedance, the microorganism is able to catalyze the oxygen reduction reaction. Finally, a general insight was achieved and the phenomena were discussed in detail from physico-electrochemical viewpoint.