Long-Term Monitoring of Bacterial Community Succession in Septic Tank by Denaturing Gradient Gel Electrophoresis of 16S rRNA Gene Fragments

Abstract

The long-term succession of bacterial communities in a medium-scale septic tank was monitored by the denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA fragments. The calculation of diversity indices from DGGE profiles indicated that the bacterial diversity in the aeration tank was significantly higher than those in the other tanks studied. Ten of the 23 sequenced DGGE bands were affiliated with beta-proteobacteria and some of these bacteria were prominent. Clustering analysis of the DGGE banding pattern revealed that spikes in feed strength caused significant changes in community structure in the raw water and aeration tanks. Dendrogram construction using the DGGE profiles of the aeration tank showed that the bacterial community structure changed by direct inputs of organic waste matter returned to the original stable community structure over time. The specification of bacteria that mainly affect the succession of the indigenous bacterial community structure was facilitated by the dendrogram construction from DGGE profiles.