Recombinant Escherichia coli HB101 harboring keratinase rKP2 from Pseudomonas aeruginosa KS-1 degraded 2% chicken feather in LB-Amp medium in 24 h. SEM analysis and detailed studies revealed that bacterial colonization of feather was a pre-requisite for degradation of feather by keratinase. The mechanism of sulfitolysis revealed involvement of free cystinyl group as a source of redox during colonization as DTNB inhibited feather degradation by rKP2. Involvement of GGT-GSH system in contribution of free cystinyl group for redox was established by using GGT knockout recombinant E. coli strain that failed to degrade feather inspite of successful colonization and keratinase production. Short term experiments further confirmed enhanced protein release from feather keratin in presence of GGT-GSH redox. In the presence of similar redox, rKP2 also degraded surrogate prion protein, Sup 35NM in 15 min at 37 degrees C, pH 7.0. (C) 2012 Elsevier Ltd. All rights reserved.