Lab 33: Nitrate Reduction (Anaerobic Respiration)

Question 1

reduction of nitrate to nitrite usually occurs? which family does it?
some are able to?

Answer 1

-under anaerobic conditions
-most members of Gram-negative Enterobacteriaceae are able to do this
-some are able to further reduce nitrite to ammonia or nitrogen gas

Question 2

denitrification

Answer 2

proceeds all the way to nitrogen gas

Question 3

whats in nitrate broth

Answer 3

contains potassium nitrate, sodium chloride, and peptone

Question 4

what reagents are used?
results?

Answer 4

-nitrate reagent A and B
-Nessler’s reagent (only if no change)
-if red before Nessler’s = pos
-if red after Nessler’s = neg
-yellow/brown after Nessler’s = pos