Anaerobic ammon ium oxidizing (anammox) bacteria oxidize ammonium and reduce nitrite, producing N2, and could play a major role in energy-optimized wastewater treatment. However, sensitivity to various environmental conditions and slow growth currently hinder their wide application. Here, we attempted to determine online the effect of environmental stresses on anammox bacteria by using an overnight batch activity test with whole cells, in which anammox activity was calculated by quantifying N2 production via headspace-pressure monitoring. A planktonic mixed culture dominated by “Candidatus Kuenenia stuttgartiensis” strain CSTR1 was cultivated in a 30-L semi-continuous stirring tank reactor. In overnight resting-cell anammox activity tests, oxygen caused strong inhibition of anammox activity, which was reversed by sodium sulfite (30 µM). The tested antibiotics sulfamethoxazole, kanamycin, and ciprofloxacin elicited their effect on a dose-dependent manner; however, strain CSTR1 was highly resistant to sulfamethoxazole. Anammox activity was improved by activated carbon and Fe2O3. Protein expression analysis from resting cells after anammox activity stimulation revealed that NapC/NirT family cytochrome c (KsCSTR_12840), hydrazine synthase, hydrazine dehydrogenase, hydroxylamine oxidase, and nitrate:nitrite oxidoreductase were upregulated, while a putative hydroxylamine oxidoreductase HAO (KsCSTR_49490) was downregulated. These findings contribute to the growing knowledge on anammox bacteria physiology, eventually leading to the control of anammox bacteria growth and activity in real-world application.
• Sulfite additions can reverse oxygen inhibition of the anammox process
• Anammox activity was improved by activated carbon and ferric oxide
• Sulfamethoxazole marginally affected anammox activity
Patescibacteria” have been estimated to account for one-quarter of the total microbial diversity on Earth, the parasitic lifestyle of which may exert a profound control on the overall microbial population size of the local ecosystems. However, their diversity and metabolic functions in marine sediments, one of the largest yet understudied ecosystems on Earth, remain virtually uncharacterized.
Chlorinated ethenes are risk drivers at many contaminated sites, and current bioremediation efforts focus on organohalide-respiring
strains to achieve detoxification. We isolated and characterized the first non-
Dehalogenimonas etheniformans” strain GP, capable of metabolic reductive dechlorination of TCE, all DCE isomers, and VC to environmentally benign ethene.
Among endosymbiotic bacterial lineages, few are as intensely studied as
, which include the causative agents of spotted fever, typhus, and anaplasmosis. However, an important subgroup called “
Midichloriaceae” receives little attention despite accounting for a third of the diversity of
and harboring a wide range of bacteria with unique features, like the ability to infect mitochondria.