Assuming that A is not changed from one experiment to the next, we determine that the proportionality constant, p, is equivalent to [E]. Currently, there is an open question about EAB permittivity and its role in delivering nutrients to the lower strata, which are expected to be nutrient starved. It is becoming clear that EABs under constant flow may benefit from advection through the interior. This achieves the activation of otherwise starved bacteria, leading to an increase in the effective enzyme concentration. Modeling has suggested that mass transport into the EAB interior is driven by flow rate and substrate concentration. We take the highest intercept value from Figure (occurring at high flow rate and high concentration) as the upper benchmark and characterize the reduction in [E] as flow rate and concentration are reduced. The resulting analysis is shown in Figure . It shows that flow rate is the most influential mechanism in accessing new catalytic regions in the EAB but that concentration can play a secondary role. A schematic of the EAB under higher acetate loadings during high flow and concentrations result in an expansion of the active regions of the EAB (Figure ), whereas under low flow rates the active EAB layer is reduced in volume (Figure ).