TY - JOUR
T1 - Survival strategy of comammox bacteria in a wastewater nutrient removal system with sludge fermentation liquid as additional carbon source
AU - Xu, Shaoyi
AU - Chai, Wenbo
AU - Xiao, Rui
AU - Smets, Barth F.
AU - Palomo, Alejandro
AU - Lu, Huijie
PY - 2022
Y1 - 2022
N2 - Complete ammonia oxidizing (comammox) bacteria are frequently detected
in wastewater biological nutrient removal (BNR) systems. This study
identified “Candidatus Nitrospira nitrosa”-like comammox
bacteria as the predominant ammonia oxidizers (97.5–99.4%) in a
lab-scale BNR system with acetate and sludge fermentation liquid as
external carbon sources. The total nitrogen and phosphorus removals of
the system were 75.9% and 86.9% with minimal N2O emission
(0.27%). Low ammonia concentration, mixotrophic growth potentials and
metabolic interactions with diverse heterotrophs collectively
contributed to the survival of comammox bacteria in the system. The
recovered draft genomes of comammox bacteria indicated their potentials
in using acetate and propionate but not butyrate. Acetate and propionate
indeed stimulated the transcription of comammox amoA genes
(up-regulated by 4.1 folds compared with no organic addition), which was
positively correlated with the ammonia oxidation rate of the community (r = 0.75, p < 0.05). Comammox bacteria could provide vitamins/cofactors (e.g., cobalamin and biotin) to heterotrophs (e.g., Burkholderiaceae),
and in return receive amino acids (e.g., phenylalanine and tyrosine)
from heterotrophs, which they cannot synthesize. Compared with comammox
bacteria, ammonia oxidizing bacteria (AOB) exhibited lower metabolic
versatility, and lacked more pathways for the synthesis of amino acids
and vitamin/cofactors, leading to their washout in the studied system.
BNRs with comammox bacteria as the major nitrifiers hold great
potentials in achieving superior performance at low aeration cost and
low N2O emission and at full-scale plants.
AB - Complete ammonia oxidizing (comammox) bacteria are frequently detected
in wastewater biological nutrient removal (BNR) systems. This study
identified “Candidatus Nitrospira nitrosa”-like comammox
bacteria as the predominant ammonia oxidizers (97.5–99.4%) in a
lab-scale BNR system with acetate and sludge fermentation liquid as
external carbon sources. The total nitrogen and phosphorus removals of
the system were 75.9% and 86.9% with minimal N2O emission
(0.27%). Low ammonia concentration, mixotrophic growth potentials and
metabolic interactions with diverse heterotrophs collectively
contributed to the survival of comammox bacteria in the system. The
recovered draft genomes of comammox bacteria indicated their potentials
in using acetate and propionate but not butyrate. Acetate and propionate
indeed stimulated the transcription of comammox amoA genes
(up-regulated by 4.1 folds compared with no organic addition), which was
positively correlated with the ammonia oxidation rate of the community (r = 0.75, p < 0.05). Comammox bacteria could provide vitamins/cofactors (e.g., cobalamin and biotin) to heterotrophs (e.g., Burkholderiaceae),
and in return receive amino acids (e.g., phenylalanine and tyrosine)
from heterotrophs, which they cannot synthesize. Compared with comammox
bacteria, ammonia oxidizing bacteria (AOB) exhibited lower metabolic
versatility, and lacked more pathways for the synthesis of amino acids
and vitamin/cofactors, leading to their washout in the studied system.
BNRs with comammox bacteria as the major nitrifiers hold great
potentials in achieving superior performance at low aeration cost and
low N2O emission and at full-scale plants.
KW - Nutrient removal
KW - Comammox
KW - Volatile fatty acid
KW - Mixotrophic growth
KW - Metabolic interaction
U2 - 10.1016/j.scitotenv.2021.149862
DO - 10.1016/j.scitotenv.2021.149862
M3 - Journal article
C2 - 34461473
SN - 0048-9697
VL - 802
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 149862
ER -