Utilization of Raw Glycerol for Pyocyanin Production from Pseudomonas Aeruginosa in Half-Microbial Fuel Cells: Evaluation of Two Electrochemical Approaches

Abstract

Power generation via glycerol in Pseudomonas aeruginosa fuel cells was evaluated under improved culture conditions using two different electrochemical systems. One used Pt-black carbon felt air cathodes and proton exchange membranes. The other used ammonia pre-treated carbon felt electrodes immersed in ferricyanide as cathode and saline bridges as a cation exchange system. In all cases, ammonium pre-treated carbon felts were used as anodes. Experiments were conducted during 120 h at 37°C. Biochemical parameters such as microbial growth, substrate consumption and pyocyanin production were evaluated. Electrochemical studies of chronoamperometry, power output generation and coulombic efficiency (CE) were also performed. Initial concentrations of 25 g L−1 of pure glycerol were used. Small differences between systems, in terms of PCN production, glycerol consumption or microbial growth were observed. Also, good results in terms of current densities (Idmax) of 42 ± 2.1 μA cm−2, CE of 48 ± 2.4% and power output densities (Pdmax) of 350 ± 17.5 mW m−2, were achieved. The power output densities were at least 4 times higher than other previously reported MFCs based also on PCN production from pure glycerol or glucose. In contrast, when both systems were supplemented with raw glycerol obtained as by-product from biodiesel industry, lower values for Idmax, CE and Pdmax ranging 23 ± 1.15 μA cm−2, 36 ± 1.18% and 240 ± 12.0 mW m−2, were respectively achieved, depending on the electrochemical system used.