the objective of present study was to evaluate the feasibility of symbiosis between bacteria and algae based on CANON process. To achieve this purpose, the nitrogen removal performances of the bioreactor were studied contrastively before and after AB biofilm formation. The concentration and physicochemical evolution of extracellular polymeric substances (EPS) were quantitatively and qualitatively investigated during the formation of AB biofilm. The nitrate removal pathway was further analyzed through batch experiments. The evolution of biofilm microbial communities was determined using 16S rRNA and 18S rRNA high-throughput sequencing techniques. The results of this research can provide novel insight for the development of green, low-carbon and sustainable wastewater treatment technology.