To the complete defined medium were added increasing

concentrations of resazurin (0.001 to 0.005%) to verify anaerobiosis of the

medium and 10 mg of solid cysteine to decrease the redox potential of the

medium. The medium was bubbled with ultrahigh-purity nitrogen for 15 min at

room temperature and then autoclaved for 30 min at 121°C. The color of the

medium changed from purple to pale yellow, confirming that the tubes were

anaerobic. please check ds medium.....

Thanks. what is the purpose of using resazurin ??