Key Laboratory of Low-Grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China. Electronic address: [Email]
Due to the small size, similar density to water, cells inoculating onto the solid carrier is a major challenge for microalgae biofilm cultivation. To reduce biofilm inoculation time, A. falcatus with long stripe were chosen as the bond linking with the main microalgae cells forming microalgae-microalgae co-flocculation by bridging and twining. The optimal matching species were S. obliquus and A. falcatus with the volume ratio of 4-1. By changing the zeta-potential of the microalgae-microalgae co-flocculation to positive and negative through pH regulating, the inoculation time was significantly shorted from 4 h to 1.5 min due to the charge neutralization. Fortunately, the added A. falcatus and pH regulation has no negative effects on biofilm growth. Inversely, the porous microstructure of microalgae-microalgae co-flocculation improve the transfer efficiency of nutrients, resulting a 90.15% increase on biomass productivity (229.15 g m-2) comparing to pure microalgae species.