Microbial diversity in fluidized pellet-bed bioreactor

To study the microbial diversity of granular sludge in fluidized pellet-bed (FPB) bioreactor, the sludge at different heights (10, 60 and 110 cm) of FPB was sampled, and the genomic DNA of microbial community was extracted directly. After purifying the genomic DNA, 16S rRNA genes were amplified, and the amplified DNA fragments were separated by denaturing gradient gel electrophoresis (DGGE). The characteristic bands of DGGE were sequenced, and the phylogenetic diversity of microbes in the FPB bioreactor was surveyed based on the homology analysis of 16S rRNA sequences. The results indicated that the obtained 18 operational taxonomic units (OTUs) all belonged to Eubacteria, of which, 61% was Proteobacteria, 17% was Actinobacteria, 11% was low G+C gram-positive bacterium, and 11% belonged to other bacterial branches.