Fig. 5

Derivative of r with respect to L. a Decoupled derivative showing rate of change in ferricyanide reduction rate as a result of changes in k(L) and A(L) for a unit mediator concentration difference between the bulk medium and cell surface, \(\left( [\hbox {Fe}^{3+}]_{{\text{b}}}-[\hbox {Fe}^{3+}]_{{\text{s}}}\right) =1\)mol m⁻³. b Derivative of ferricyanide reduction rate with respect to cell length