The testing for indole production is important to know the
6 P.R. Yaashikaa et al. / Microbial Pathogenesis 99 (2016) 5e13tryptophanase production. The test organism was grown in tryptone media. Indole is a component of the amino acid tryptophan.
Kovac's reagent which contains the Para di methyl amino benzaldehyde, detects indole production. This reacts with indole to produce a red color compound. The test tubes containing tryptone
were inoculated with the inoculums and incubated at 37 C for 2e4
days and indole production was tested by adding 2 to 3 drops of
Kovac's reagent. The appearance of cherry red color indicates the
presence of indole