Bacterial communities in residential wastewater treatment plants are physiologically adapted to high concentrations of quaternary ammonium compounds
Fecha
2023-08-28
Tipo
artículo original
Autores
Chacón Jiménez, Luz María
Rojas Jiménez, Keilor Osvaldo
Arias Andrés, María de Jesús
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Resumen
Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) widely used
as the active ingredient of disinfectants. Its excessive discharge into wastewater is
constant and in high concentrations, likely affecting the physiology of microbial com munities. We compared the physiological community profile of activated sludge (AS)
bacteria with and without prior in vitro exposure to a high concentration of BAC
(10 mg L−1). We measured the community functional diversity, carbon substrate mul tifunctionality, and the median effective concentration that inhibits carbon respiration
(EC50) using Biolog EcoPlates supplemented with a gradient of 0–50 mg L−1 of BAC.
Surprisingly, we did not find significant differences in the physiological parameters
among treatments. Certain abundant bacteria, including Pseudomonas, could explain
the community’s tolerance to high concentrations of BAC. We suggest that bacterial
communities in wastewater treatment plants’ AS are “naturally” adapted to BAC due
to frequent and high-dose exposure. We highlight the need to understand better the
effects of QACs in wastewater, their impact on the selection of tolerant groups, and
the alteration in community metabolic profiles.
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Palabras clave
Activated sludge, Benzalkonium chloride, EcoPlate system, Functional traits, Pseudomonas