Enhanced extraction of extracellular polymeric substances from biofilms by alternating current

Abstract

The extraction of extracellular polymeric substances (EPS) including polysaccharides and proteins from aerobic biofilms using either EDTA or NaOH was enhanced by alternating current especially within the first 0.5 h of current application. At 60 mA and 50 Hz, the average extraction rate of polysaccharides within the first 0.5 h using EDTA was 8.3 mg h−1 g TS−1 (TS: total solid, dry wt), 1.6 times of that without current, and that of proteins was 2.5 mg h−1 g TS−1, 1.2 times higher. The extraction of polysaccharides was maximal at around 500 Hz while that of proteins was less affected by increasing the current frequency.