The present review deals with fungal keratinases including that of dermatophytes. Bacterial keratinases were also included. Temperature and substrate relationship keratinase production has also been discussed. Keratin degradation and industrial involvement of keratinase producing fungi is also reviewed.

Based on previous screening for keratinolytic nonpathogenic fungi, Paecilomyces marquandii and Doratomyces microsporus were selected for production of potent keratinases. The enzymes were purified and their main biochemical characteristics were determined (molecular masses, optimal temperature and pH for keratinolytic activity, N-terminal amino acid sequences). Studies of substrate specificity ...

Keratinases are proteolytic enzymes predominantly active when keratin substrates are available that attack disulfide bridges in the keratin to convert them from complex to simplified forms. Keratinases are essential in preparation of animal nutrients, protein supplements, leather manufacture, textile processing, detergent formulation, feather meal processing for feed and fertilizer, the pharmac...

Two novel extracellular keratinases were produced by Actinomadura keratinilytica strain Cpt20. Both enzymes purified to homogeneity using heat-treatment (60 °C for 30 min) and ammonium sulfate salt fractionation (40 %–70 %), followed anion-exchange chromatography with fast protein liquid (FPLC) system. The keratinases, designated as KERA-71 KERB-19, are monomeric named according their molecular...

Four extracellular keratinases (designated KI, KII, KIII, and KIV) were produced during submerged aerobic cultivation in a medium containing native human foot skin (NHFS) for enzyme synthesis. The molecular weights, determined by SDS-PAGE, were 25, 50, 34, and 19 kDa, respectively. Gel filtration of the four purified enzymes in native conditions indicated that active keratinase KI is a novel ho...

Keratin is a fibrous and recalcitrant protein found in feathers, nails, horns, hooves, the epidermis of skin. The presence high degree disulfide bonds, hydrogen hydrophobic interactions makes them resistant to mechanical stress are not degraded by common proteases such as trypsin, pepsin, papain. Due slow degradation keratinous protein, accumulation solid wastes from poultry, slaughterhouse, te...

Keratinolytic abilities of Bacillus polymyxa B20 and B. cereus B5esz were evaluated in liquid cultures in mineral media containing chicken feathers. Both tested strains were capable of effective liquefying and biodegradation of feather keratin, up to 56.5 – 72.1% in ten-day cultures, releasing considerable amounts of hydrolysis products. Tested bacteria were mesophilic species, producing highes...

Bacillus subtilis strain S1-4, with the capacity to efficiently degrade feathers, was isolated from chicken feathers. Sequencing showed that the genome of strain S1-4 differs from that of other B. subtilis strains, with limited insertions and deletions. The genome encodes multiple extracellular proteases and keratinases.

Dehairing is one of the highly polluting operations in the leather industry. The conventional lime-sulfide process used for dehairing produces large amounts of sulfide, which poses serious toxicity and disposal problems. This operation also involves hair destruction, a process that leads to increased chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solid (TSS) l...