Lecture 34

Question 1

What is the name of the enzymes that converts N2-> NH4+?

Answer 1

Nitrogenase

Question 2

What is the enzyme responsible for ammonium oxidation? What is the reaction?

Answer 2

Ammonium monooxygenase

NH4+ ==> NO2-

Question 3

What is the enzyme responsible for nitrite oxidation? What is the reaction?

Answer 3

Nitrite oxidoreductase (NOR or NXR)

NO2- ==> NO3-

Question 4

What are examples of bacteria that have ammonium AMO enzyme?

Answer 4

Nitrosomonas
Nitrosococcus
Thaumarchaeota

Question 5

What are examples of bacteria that have NOR or NXR enzyme?

Answer 5

Nitrospira
Nitrobacter
Nitrospina

Question 6

What is the nitrification reaction? in what condition does it usually happen?

Answer 6

Conversion of ammonium to NO2- and NO3-

Aerobic conditions except for ntrospira (commamox) => usually under low O2 (and low HN4+) niche

Question 7

What is commamox? What is the reaction?

Answer 7

Complete ammonium oxidation by single species

NH4+ => => NO3-

Question 8

What is anammox? What is the reaction?

Answer 8

Anaerobic Ammonium oxidation

NH4+ +NO2- => N2

Oxidation of NH4+ using NO2- formed via suboxic nitrification yields N2 and perhaps NO3-

Question 9

When was anammox first detected?

Answer 9

First detected in anaerobic wastewater treatment systems

Question 10

What are anammox bacteria? Where is anammox active?

Answer 10

Anammox bacteria are slow-growing autotrophs belonging to the phylum Planctomycetes

Could be activein marine sediments, oxygen minimum zones, other anaerobic environments