The Reduction of 2,3,5-Triphenyltetrazolium Chloride by Penicillium chrysogenum

Abstract

Some proof of the theory that penicillin is produced by a relatively inactive mold has been obtained by using the en-zymic reduction of 2,3,5-triphenyltetrazolium chloride (TTC) as an indicator of cell viability. P. chrysogenum Q176 was grown as described by Koffler and harvested. The pellets were washed, suspended in [image]/15 phosphate soln. and torn apart in a Waring Blendor. After blending, a buffer soln. of TTC was added to give a final concn. of 0.5%. Under these conditions, active mold cells reduce the dye to a deep red color in 20 min. at 30[degree]C. The ability of P. chrysogenum of different ages to reduce the TTC was observed as well as the yield of penicillin at the time of harvest. The older cells produced a greater yield of penicillin but showed less reduction of TTC.