Denitrification performance and microbial versatility in response to different selection pressures

• Published in: Bioresource technology Vol. 281; pp. 72 - 83
• Main Authors: Pishgar, Roya, Dominic, John Albino, Sheng, Zhiya, Tay, Joo Hwa
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2019
• Subjects: Acinetobacter; Aerobic denitrification; Aerobic granulation; ammonium nitrogen; Arcobacter; biodiversity; biomass; Comamonas; denitrification; Denitrifiers; denitrifying microorganisms; Ecological niche; Flavobacterium; microbial communities; nitrate nitrogen; nitrates; nitrification; nitrite nitrogen; nitrites; nitrogen; nitrogen oxides; Nitrogen removal mechanism; Pseudomonas; selection pressure; Suspended biomass; Thauera; Zoogloea; Denitrifiers; Suspended biomass; Aerobic granulation; Aerobic denitrification; Ecological niche; Nitrogen removal mechanism
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2019.02.061

[Display omitted] •Aerobic and anoxic suspended biomass could remove diverse NOx− concentrations.•Denitrifying community significantly altered under different incubation conditions.•Interspecies interactions possibly limited aerobic denitrification capacity.•Granular biomass removed nitrogen via heterotrophic nitrification/denitrification.•Microbial selection and nitrogen removal pathway depend on nourishment condition. This study investigated functional dynamics of microbial community in response to different selection pressures, with a focus on denitrification. Suspended-biomass experiments demonstrated limited aerobic and relatively higher anoxic nitrate and nitrite reduction capabilities; the highest NO2-N and NO3-N removal rates were 1.3 ± 0.1 and 0.74 ± 0.01 in aerobic and 1.4 ± 0.05 and 3.4 ± 0.1 mg/L.h in anoxic media, respectively. Key potential denitrifiers were identified as: (i) complete aerobic denitrifiers: Dokdonella, Flavobacterium, and Ca. Accumulibacter; (ii) complete anoxic denitrifiers: Acinetobacter, Pseudomonas, Arcobacter, and Comamonas; (iii) incomplete nitrite denitrifier: Diaphorobacter (aerobic/anoxic), (iv): incomplete nitrate denitrifiers: Thauera (aerobic/anoxic) and Zoogloea (strictly-aerobic). Granular biomass removed 72 mg/L NH4-N with no NOx− accumulation. Heterotrophic nitrification and aerobic denitrification were proposed as the principal nitrogen removal pathway in granular reactors, potentially performed by two key organisms Thuaera and Flavobacterium. Biodiversity analysis suggested that the selection pressure of nourishment condition was the decisive factor for microbial selection and nitrogen removal mechanism.