Bacterial community dynamics involved in Reactive Orange M2R dye degradation using a real time quantitative PCR and scale up studies using sequence batch reactor

Bacterial consortium volatile suspended soil (VSS) (Vatva soil sample) with a capability of azo dye Reactive Orange M2R (ROM2R) decolorization and degradation (shown in our earlier studies using Fourier transform infrared spectroscopy (FTIR) and phytotoxicity studies) was isolated from industrial wastewaters by enrichment culture technique. The present study was carried out to study bacterial population dynamics in consortium Vatva soil sample (VSS) during azo dye ROM2R degradation and to identify the consortium members that were actively involved in the degradation process. To achieve this goal, a real-time Polymerase chain reaction (PCR) assay targeting species-specific region of 16S rDNA of each consortial bacteria was developed to provide quantitative information about the bacterial abundance during azo dye degradation. The real-time PCR assay indicated that Pseudomonas aeruginosa (VSS-6) dominated consortium bacterial community during the active continuous bioremediation process. Attempt has been made to scale up from 100 ml volume to 10 L operation volume with intermittent additions (batch fed loadings) in a Sequence batch reactor (SBR). The development of VSS consortium biomass (MLVSS), changes in COD and biochemical oxygen demand, and the dye degradation were studied under conditions simulating the operations of biological effluent treatment in an attempt to develop a commercially applicable dye effluent treatment process unit.