posted on 2022-12-28, 18:42authored byHong Sun, Qiang Tang, Yang Li, Zi-Han Liang, Feng-He Li, Wen-Wei Li, Han-Qing Yu
Microbial
extracellular electron transfer (EET) is the basis for
many microbial processes involved in element geochemical recycling,
bioenergy harvesting, and bioremediation, including the technique
for remediating U(VI)-contaminated environments. However, the low
EET rate hinders its full potential from being fulfilled. The main
challenge for engineering microbial EET is the difficulty in optimizing
cell resource allocation for EET investment and basic metabolism and
the optimal coordination of the different EET pathways. Here, we report
a novel combinatorial optimization strategy with a physiologically
adapted regulatory platform. Through exploring the physiologically
adapted regulatory elements, a 271.97-fold strength range, autonomous,
and dynamic regulatory platform was established for Shewanella oneidensis, a prominent electrochemically
active bacterium. Both direct and mediated EET pathways are modularly
reconfigured and tuned at various intensities with the regulatory
platform, which were further assembled combinatorically. The optimal
combinations exhibit up to 16.12-, 4.51-, and 8.40-fold improvements
over the control in the maximum current density (1009.2 mA/m2) of microbial electrolysis cells and the voltage output (413.8 mV)
and power density (229.1 mW/m2) of microbial fuel cells.
In addition, the optimal strains exhibited up to 6.53-fold improvement
in the radionuclide U(VI) removal efficiency. This work provides an
effective and feasible approach to boost microbial EET performance
for environmental applications.