Nitrate Respiration (Reduction)

These flashcards cover key concepts related to nitrate respiration and reduction, including processes, enzymes, and testing methods.

Nitrate reductase

An enzyme produced by some microbes that reduces nitrate (NO3-) to nitrite (NO2-), involved in nitrate respiration.

Nitrite reductase

An enzyme produced by some microbes that further reduces nitrite to nitrous oxide (N2O) and to nitrogen gas (N2) or assimilates it as ammonia (NH3) into amino acids.

Nitrate respiration

The process whereby some aerobic microbes use nitrate as the terminal electron acceptor under anaerobic or low oxygen conditions, reducing nitrate to nitrite.

Denitrification

The process of reducing nitrite to gas or ammonia.

Aerobic respiration

A metabolic process that uses oxygen as the terminal electron acceptor.

Anaerobic conditions

A state in which oxygen levels are low or absent, allowing certain microbes to utilize substances like nitrate for respiration.

Durham tube

A device used to detect gas production in microbial fermentation tests.

Positive test for nitrite

Indicated by a color change when reagents are added to a broth, confirming nitrate has been reduced.

Negative nitrite test

Means that nitrite was not detected, further testing is required even if gas is present in the Durham tube.

Nitrate broth

A growth medium used to detect nitrate reduction by inoculating with microorganisms.