Microalgae have great potential as a feedstock for biofuel production. Continuous operation is an important benefit of the continuous electrolytic microalgae (CEM) harvest system, but it is necessary to optimize cultivability and recovery efficiency in order to improve overall performance. Two pairs of best-candidate electrodes for polarity exchange (PE) were examined to improve these two key factors: (i) aluminum and dimensionally stable anode (Al-DSA), and (ii) Al-platinum (Al-Pt). Al-DSA was better than Al-Pt because it led to less cell damage and was less expensive. Moreover, cell viability and recovery were improved by optimizing the timing of PE. A P1:P2 ratio of 1:1.5 at 5 min and 1:1.2 at 10 min yielded the best results, with greatly reduced electricity consumption and enhanced cell viability and recovery. The CEM harvest system appears to be a well-suited option for the harvest of microalgae for biofuel production. (C) 2012 Elsevier Ltd. All rights reserved.