activated sludge metagenome Raw sequence reads

A novel Anoxic-Aerobic Process (AnAP) that completely eliminated the anaerobic process was optimized and operated for the simultaneous remediation of phosphate, nitrate and chemical oxygen demand (COD) from industrial effluents. Two sequential batch reactors (SBR) with AnAP were established for treatment of effluent from two industries; phosphate fertilizer (AnASBR_PPL) and dairy industry (AnASBR_DW). The adaptability of the bacterial consortium in the SBRs, dominated by denitrifying phosphate accumulating organism (DNPAOs) facilitates the stable performance of AnAP process for simultaneous nutrient and COD removal. Up to 90% and ~80% of COD removal were achieved in AnASBR_PPL and AnASBR_DW, respectively. Nearly complete denitrification was observed along with phosphate removal accounted for ~90% in both the reactors. Granulation of sludge has been widely reported in aerobic reactors however, interestingly in this study partial granulation of the sludge was observed in both the AnASBRs which facilitates the microorganisms to uptake a minimal amount of phosphate and nitrate even under the aerobic condition. The underlying mechanism of DNPAOs, and other associated microbes in the consortium were investigated for microbial diversity by 16S rDNA based targeted amplicon sequencing using Illumina platform and imputed metagenomic analysis. Dominance of Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria and Bacteroidia was observed in AnASBRs. At steady-state operation, the identity of the core community members remained relatively stable, but their relative abundances changed considerably in both the reactors as a function of varying industrial effluent. The dominant bacteria displayed similar diversity in case of functional analysis. The dominant strains were the vital contributor to the gene pool encoding for denitrification, dephosphatation, TCA cycle, glycolysis, EPS production, and polyhydroxyalkanoate (PHA) storage etc. Few less abundant but persistent species were also detected as contributors to these functional groups. It unveiled the preference of TCA cycle over conventional glycogen metabolism by DNPAOs for simultaneous nutrient and COD removal.