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Main sol. 339

Internal Solution-ID: S651

Equipment needed: Filter Autoclave Hungate tubes Gassing station
Compound Amount Unit Conc. [g/L] Conc. [mM]
dehydrated Wilkins-Chalgren medium
(Oxoid CM0643)
33.0 g 33 -
Sodium resazurin
(0.1% w/v)
0.5 ml 5.0e-4 0.002
L-Cysteine HCl 0.3 g 0.3 1.903
Distilled water 1000.0 ml - -
1 Dissolve 33.0 g/l dehydrated Wilkins-Chalgren medium (Oxoid CM0643) in distilled water and add 0.5 ml/l Na-resazurin solution (0.1% w/v), bring to the boil and cool to room temperature while sparging with 100% N2 gas. Add L-cysteine-HCL x H2O (0.3 g/l), dispense the medium under same gas atmosphere into anoxic Hungate-type tubes or serum vials and autoclave. After autoclaving check pH and adjust to pH 6.8 - 7.0, if necessary.
2 Note: In case resazurin is not colourless addition of 10 - 20 mg sodium dithionite per liter (e.g. from 5% (w/v) solution, freshly prepared under N2 and filter-sterilized) can be used to completely reduce the medium.