Mining and assessment of catabolic pathways in the metagenome of a common effluent treatment plant to induce the degradative capacity of biomass

•Metagenome analysis of activated biomass treating industrial wastewater.•Taxonomic data reveals nine different phyla.•Central meta-cleavage pathway genes dominate in CETP.•Successful scale up of lab-scale experiments to pilot-scale treatment.•Demonstration of improved efficiency of wastewater treatment at pilot scale.

Metagenome analysis was used to understand the microbial community in activated sludge treating industrial wastewaters at a Common Effluent Treatment Plant (CETP) in South India. The taxonomic profile mapped onto National Center for Biotechnology Information (NCBI) taxonomy using MEtaGenome ANalyzer (MEGAN), demonstrated that the most abundant domain belonged to prokaryotes, dominated by bacteria. Bacteria representing nine phyla were identified from the sequence data including representatives from two new phyla, Synergistetes and Elusimicrobia. Functional analysis of the metagenome, with specific reference to the metabolism of aromatic compounds, revealed the dominance of genes of the central meta-cleavage pathway. This information was used to improve the degradative efficiency in the wastewater treatment plant. A pilot scale plant was set up with 200 L of activated sludge using salicylate induced sludge and results demonstrated 52% removal in chemical oxygen demand (COD) against non-induced biomass.