To investigate the effect of selective culturing on microorganisms and functional role of electrical active bacteria in biofilm,some exoelectrogens were isolated from microbial fuel cell( MFC) anodic biofilm using Hungate roll-tube technique with iron oxide as indicator. At the same time,the dynamics of the microbial community structure was monitored during the pure culture isolation. The results show that maximum voltages of MFCs feeding with lactic acid,acetic acid and steroid wastewater are 0. 57,0. 60 a...