TY - JOUR
T1 - Cometabolic biotransformation and microbial-mediated abiotic transformation of sulfonamides by three ammonia oxidizers
AU - Zhou, Li-Jun
AU - Han, Ping
AU - Yu, Yaochun
AU - Wang, Baozhan
AU - Men, Yuijie
AU - Wagner, Michael
AU - Wu, Qinglong
PY - 2019
Y1 - 2019
N2 - The abilities of three phylogenetically distant ammonia oxidizers, Nitrososphaera gargensis, an ammonia-oxidizing archaeon (AOA); Nitrosomomas nitrosa Nm90, an ammonia-oxidizing bacterium (AOB); and Nitrospira inopinata, the only complete ammonia oxidizer (comammox)available as a pure culture, to biotransform seven sulfonamides (SAs)were investigated. The removals and protein-normalized biotransformation rate constants indicated that the AOA strain N. gargensis exhibited the highest SA biotransformation rates, followed by N. inopinata and N. nitrosa Nm90. The transformation products (TPs)of sulfadiazine (SDZ), sulfamethazine (SMZ)and sulfamethoxazole (SMX)and the biotransformation mechanisms were evaluated. Based on the analysis of the TP formulas and approximate structures, it was found that during biotransformation, i)the AOA strain carried out SA deamination, hydroxylation, and nitration; ii)the AOB strain mainly performed SA deamination; and iii)the comammox isolate participated only in deamination reactions. It is proposed that deamination was catalyzed by deaminases while hydroxylation and nitration were mediated by nonspecific activities of the ammonia monooxygenase (AMO). Additionally, it was demonstrated that among the three ammonia oxidizers, only AOB contributed to the formation of pterin-SA conjugates. The biotransformation of SDZ, SMZ and SMX occurred only when ammonia oxidation was active, suggesting a cometabolic transformation mechanism. Interestingly, SAs could also be transformed by hydroxylamine, an intermediate of ammonia oxidation, suggesting that in addition to enzymatic conversions, a microbially induced abiotic mechanism contributes to SA transformation during ammonia oxidation. Overall, using experiments with pure cultures, this study provides important insights into the roles played by ammonia oxidizers in SA biotransformation.
AB - The abilities of three phylogenetically distant ammonia oxidizers, Nitrososphaera gargensis, an ammonia-oxidizing archaeon (AOA); Nitrosomomas nitrosa Nm90, an ammonia-oxidizing bacterium (AOB); and Nitrospira inopinata, the only complete ammonia oxidizer (comammox)available as a pure culture, to biotransform seven sulfonamides (SAs)were investigated. The removals and protein-normalized biotransformation rate constants indicated that the AOA strain N. gargensis exhibited the highest SA biotransformation rates, followed by N. inopinata and N. nitrosa Nm90. The transformation products (TPs)of sulfadiazine (SDZ), sulfamethazine (SMZ)and sulfamethoxazole (SMX)and the biotransformation mechanisms were evaluated. Based on the analysis of the TP formulas and approximate structures, it was found that during biotransformation, i)the AOA strain carried out SA deamination, hydroxylation, and nitration; ii)the AOB strain mainly performed SA deamination; and iii)the comammox isolate participated only in deamination reactions. It is proposed that deamination was catalyzed by deaminases while hydroxylation and nitration were mediated by nonspecific activities of the ammonia monooxygenase (AMO). Additionally, it was demonstrated that among the three ammonia oxidizers, only AOB contributed to the formation of pterin-SA conjugates. The biotransformation of SDZ, SMZ and SMX occurred only when ammonia oxidation was active, suggesting a cometabolic transformation mechanism. Interestingly, SAs could also be transformed by hydroxylamine, an intermediate of ammonia oxidation, suggesting that in addition to enzymatic conversions, a microbially induced abiotic mechanism contributes to SA transformation during ammonia oxidation. Overall, using experiments with pure cultures, this study provides important insights into the roles played by ammonia oxidizers in SA biotransformation.
KW - Abiotic transformation
KW - Ammonia oxidizers
KW - Biotransformation
KW - Cometabolism
KW - Sulfonamides
UR - http://www.scopus.com/inward/record.url?scp=85065756008&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2019.05.031
DO - 10.1016/j.watres.2019.05.031
M3 - Journal article
SN - 0043-1354
VL - 159
SP - 444
EP - 453
JO - Water Research
JF - Water Research
ER -