Monitoring the microbial population dynamics at the start-up stage of wastewater treatment reactor by terminal restriction fragment length polymorphism analysis based on 16s rDNA and rRNA gene sequences

The microbial population dynamics at the start-up stage of a wastewater treatment reactor was investigated using terminal restriction fragment length polymorphism (T-RFLP) analysis based on 16S rDNA and rRNA gene sequences. The results of fragment peaks suggested that the number and activity of nitrifying bacteria increased in association with the start of nitrification, and the relative ratios of 16S rRNA of these bacteria changed prior to those of the 16S rDNA. Furthermore, multidimensional scaling (MDS) analysis revealed that the 16S rRNA exhibited wider dispersion than the 16S rDNA at the start-up stage, indicating that the diversity of 16S rRNA in the microbial communities was strongly affected by environmental changes.