Nitrate Reduction Test {Lab 8 - May 21, 2015}

     For this test, we determined if our bacteria was able to reduce nitrate ions to either nitrite ions or nitrogen gas. 

Materials:

• Nitrate broth tube
• Nitrate reagent A (sulfanilic acid)
• Nitrate reagent B (dimethyl-alpha-naphthylamine)
• gloves
• Unknown bacteria

Procedure:

     Using aseptic techniques, we inoculated the nitrate broth with our unknown bacteria and incubated it. After incubation, we added 5 drops of reagent A and 5 drops of reagent B, then gently shaker the tube to mix the reagents with the broth. A pink-red color appeared indicating the test was positive for nitrate reduction. 

Elisabeth mixing the
nitrate reagents into
the broth

The nitrate broth
tube after incubation

Positive Nitrate Reduction Test

Results/application:
     This test is used in clinical microbiology to detect nitrate reductase produced by some intestinal bacteria and some strains of veillonella.