We are seeking assistance in the preparation of pre-reduced media for the
cultivation of anaerobic bacteria. We are using the preparation methods
of Holdemann et al., Anaerobic Laboratory Manual, 4th edn. (1977). We
have found that the indicator (resazurin) does not undergo a colour
change after boiling, as recorded in the manual, ie. from purple to
colourless in 5-10 min. In our experiments the indicator changes from
purple to pink in 20 min and does not change to colourless, even after
prolonged boiling. After cysteine hydrochloride addition and
autoclaving, the indicator in the media changed from colourless to purple
even when placed in an anaerobic chamber. Cooling the media under
nitrogen gas after boiling has also been unsuccessful. Is anyone able to
help us? Thank you
Loren Goldstone and Kimoni Rampersad
Technikon Natal, Durban, South Africa
E-mail: research at einstein.ntech.ac.za
