This study used a combination of Denaturinf gradient gel electrophoretic analysis(DGGE) and 16S rDNA sequencing to identify the purple non-sulfur bacteria(PNSB) that were cultivated by food industry wastewater in the anaerobic membrane photo-bioreactor. Organic removal and biomass production and characteristics were accomplished via an explicit examination of the long term performance of the photo-bioreactor fed with real wastewater.With the support of infra-red light transmitting filter, PNSB could survive and maintain in the system even under the continual fluctuations of influent wastewater characteristics. The average BOD and COD removal efficiencies were found at the moderate range of 51% and 58%, respectively. The pure strain of Rps. Palustris was used and compared with 16S rDNA sequences in microbial sludge obtained from the photo-bioreactor along the operation period. The DNA sequences were shown to be 100% identical to the DNA sequence of the control strain, Rps. Palustris.The presence of Rhodopseudomonas palustris and significant changes in the photosynthetic bacterial community within the system.