KIA: Kligler Iron Agar Used For The Bacterial Growth.

In the culture medium, meat peptone ane trypsin provides adequate nutrients for bacterial development. Lactose and glucose are fermentable carbohydrates. Sodium thiosulfate is the necessary substrate for the production of hydrogen sulfide.

Ion and ammonium citrate is the source of Fe3+ ions, which combine with hydrogen sulfide and produce sulfide of iron, black. Phenol red is the PH indicator and the sodium chloride maintains the osmotic balance. 

Agar is the solidifying agent. By fermentation of sugars, acids are produced that are detected by means of the red phenol indicator, which turns yellow in an acidic medium. 

Results analysis:

Observe the colour of the culture medium and gas production. 

1. Alkaline surface/ acid depth (red peak/ yellow background), The microorganism only ferments glucose.

2. Acid surface/ acid depth (yellow peak/ yellow background), The microorganism ferments glucose and lactose.

3. Alkaline surface/ Acid depth (red peak/red background), the microorganism is a non-fermenter of sugars.

4. The presence of bubbles or the rupture of the culture medium indicates that the microorganism produces gas.

5. The blackening of the medium indicates that the microorganism produces hydrogen sulfide.