Cyclic voltammograms (CVs) obtained from the electroactive biofilms.

<p>A) Nonturnover CVs recorded in acetate-depleted medium at scan rates ranging from 0.5 to 200 mV s⁻¹ (as indicated). B) Nonturnover CV recorded at the scan rate of 0.5 mV s⁻¹. The two redox couples <i>E_f,1</i> and <i>E_f,2</i> are centered at the formal potentials of −407 mV and −331 mV, respectively. <i>E_mean</i>, centered at −369 mV, indicates the arithmetic average of <i>E_f,1</i> and <i>E_f,2</i>. C) CVs of an electroactive biofilm metabolizing acetate (<i>i.e.</i>, turnover conditions), recorded at a scan rate of 0.5 mV s⁻¹. D) First derivatives of the turnover voltammetric curve performed at 0.5 mV s⁻¹. <i>E_f</i> represents the putative electron-transfer site, centered at −368 mV.