Materials: 

- Methanol

- 37% hydrochloric acid

- Centrifuge

- Tubes

Procedure:

Spin down the bacterial solution at 4500g for 10 minutes.

Remove culture media, weigh the remaining pellet, add the same amount of methanol and vortex for 5 minutes. Separate supernatant and pellet and acetify each with about 300µl of 37% hydrochloric acid till the color turns to red. 

Spin down the resolved pellet at 13,3g for 10 minutes and Remove supernatant.

The anthocyanidin is present in the organic and the aqueous phase; the color can be changed by adjusting the pH-value.