Electrochemical regulation of microbial growth on disposable screen printed carbon electrodes

Herein we report an effective method to enhance microbial immobilization on screen-printed carbon electrode (SPCE) surface by electrochemical regulation of redox potential. This technique could deliver a prospective electrode for microbial biofuel cell and other applications. A phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris CGA009 was selected as a model organism to examine the proposed approach. Scanning the electrode between −0.7 to 0.3 V (vs. Ag/AgCl) at 70 mV/s for 50 cycles (∼24 min), placed in the growth medium with bacteria, significantly increased microbial adhesion when compared to SPCE without electrochemical stimulation. The electron-transfer effect between the adsorbed microorganism and electrode surface was further studied by AC impedance spectroscopy to confirm the accelerated microbial immobilization. Stable photosynthetic electron transport chain from immobilized bacteria through SPCE was achieved.