Reduction of disulfide bonds by Streptomyces pactum during growth on chicken feathers

For disintegration of chicken feathers by Streptomyces pactum, keratinolytic proteinases and extracellular reduction of disulfide bonds were necessary. Conditions for disulfide reduction were examined with oxidized glutathione as model substrate. The reduction of glutathione depended on the presence of metabolically active cells. The mycelium also reduced tetrazolium dyes and cystine.