Relationship assessment of microbial community and cometabolic consumption of 2-chlorophenol

Abstract The relationship of microbial community and cometabolic consumption of 2-chlorophenol (2-CP) in a nitrifying sequencing batch reactor (SBR) was studied. The assessment of the population dynamics of the nitrifying sludge during the cometabolic 2-CP consumption with increasing ammonium (NH 4 + ) concentrations in the SBR showed the presence of 39 different species of which 10 were always present in all cycles. Fifty-five percent of the species found were grouped as Proteobacteria (45% as β-proteobacteria and 10% as γ-proteobacteria class), 30% as Acidobacteria, and 15% as Deinococcus-Thermus phyla. NH 4 + and cometabolic 2-CP consumption could be related to the presence and permanence of ammonium-oxidizing bacteria (AOB) species and heterotrophic bacteria, while the complete nitrification to the presence of nitrite-oxidizing bacteria (NOB) species. A correlation analysis showed that the complete and stable nitrifying performance (NH 4 + consumption efficiencies (ENH 4 + -N) > 99% and nitrate production yields (YNO 3 − -N) between 0.93 and 0.99), as well as the increase in specific rates (ammonium (qNH 4 + -N) and 2-CP (q2-CP-C) consumption and nitrate production (qNO 3 − -N)), was associated with the homogeneity of the bacterial community ( J index = 0.99). The increase in the proportion of individuals of AOB species such as Nitrosomonas oligotropha and Nitrosomonas marina was associated with the increase in qNH 4 + -N ( r ≥ 0.69) and q2-CP-C ( r ≥ 0.64) and, therefore, with the 2-CP cometabolic consumption in the SBR. Finally, the increase in the proportion of individuals of heterotrophic species such as Dokdonella ginsengisoli , Deinococcus peraridilitoris , Truepera radiovictrix , and Stenotrophobacter terrae was associated with the increase in q2-CP-C ( r ≥ 0.59). Key points • Thirty-nine bacterial species were identified in the nitrifying sludge population of the SBR. • β-Proteobacteria and Acidobacteria were the prevalent (85%) bacterial groups. • AOB and heterotrophic bacteria participate in NH 4 + and cometabolic 2-CP consumption. Graphical abstract