The Effect of Anode Hydrodynamics on the Sensitivity of Microbial Fuel Cell Based Biosensors and the Biological Mechanism

Abstract Fluid dynamics in the anodic chamber of a microbial fuel cell (MFC) is a key factor affecting the distribution of substrates and the efficiency of mass transport. However, the effect of hydrodynamics on MFC based biosensor (MFC-Biosensor) sensitivity has not been established. In this study, the three-dimension anode flow field of a two chamber MFC was visualized, and anodic configuration optimized by a reasonable serpentine flow field and inlet/outlet settings. Through optimization, the proportion of the dead zone in the anodic configuration decreased by 14.1%, and the velocity at the anode surface increased by 334.6% with better homogeneity of distribution. Moreover, electricity production and sensitivity for the detection biotoxicity at MFC-Biosensors improved by 23.1% and 46.1-52.3%, respectively. Biofilm viability analysis further proved that the enhanced surface velocity was of benefit for the permeation of toxicants into anodic biofilms, thus improving the sensor performance.