Fig. 5A: Production of Indole but No Hydrogen Sulfide in SIM Medium

If indole is produced from the breakdown of the amino acid tryptophan, the Kovac's reagent, when added, will turn red. If hydrogen sulfide is not produced, the agar does not turn black.

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Microbiology Laboratory Manual by Gary E. Kaiser, PhD, Professor of Microbiology
is licensed under a Creative Commons Attribution 4.0 International License.
Last updated: September, 2017