"Urease Test: If a microorganism produces urease, it can break down urea in the media. Ammonia is an alkaline product of this enzymatic reaction and changes the color of the pH indicator (phenol red) to pink.\n\nCitrate Test: If a microorganism produces citrase, citrate in the media is broken down to oxaloacetic acid and acetic acid. The oxaloacetic acid is further oxidized to pyruvic acid and CO2. The CO2 combines with Na in the media to form sodium bicarbonate. This is an alkaline product that changes the pH indicator (bromophenol blue) from green to blue.\n\nSIM Test\n\nS-H2S production: similar process to KIA (above).\n\nI-Indole production: tryptophan is broken down to ammonia, pyruvic acid, and indole. The indole reacts with Kovac’s reagent to produce a red color.\n\nM-motility: motility is observed as growth radiating outward along the length of the stab line.\n\nOxidase Test: If the microorganism has cytochrome c then they oxidize the TMPD to a dark purple. Microorganisms that lack cytochrome c can still use oxygen as a terminal electron acceptor but simply do not use cytochrome c."