Purification And Characterization Of A Keratinase From Chryseobacterium Sp.

Chryseobacterium sp.strain has been described as a highly keratinolytic bacterium A keratinase was purified from Chryseobacterium sp.culture by ammonium sulfate fractionation precipitation,Q-Sepharose^TMFast Flow chromatography and Sephadex G-75 gel filtration This enzyme showed a monomeric protein with an estimated molecular masses of 30 kDa by SDS-PAGE analysis.The enzyme was stable in a broad range of pH(7-9)and temperature(30-50℃) profile with optimums at pH8 and 40℃.Keratinase activity increased substantially in presence of Ca²⁺,Mg²⁺,K⁺ and was inhibited in presence of Fe³⁺,Co²⁺,Zn²⁺,Cu²⁺. PMSF strongly inhibited the keratinolytic activity indicating that the keratinase belongs to the serine protease family.EDTA partly inhibited the keratinolytic activity implying the importance of cations as stabilizing agents.Glycerol in the concentration of 5%(v/v)showed stimulatory effects on the keratinase activity instead of ethanol.The purified Keratinase was able to hydrolyze different keratin substrates(feather, wool,hair,Azure keratin)showing its broad keratinolytic activity.The values of K_m and V_maxcalculated from Lineweaver-Burk plots were 15.8mg/ml and 2500(1000·A280/ml/min)respectively with wool keratin substrate.The keratinase also posses proteolytic activity to degrade casein and azocasein.Savinase 16L(Novozyme),Transglutaminase(Ajinomoto)and Keratinase were selected to treat wool fabrics for shrink-resistance.Non-chlorine oxidant H₂O₂ was used for pretreatment The results showed that the effective shrinkproofing can be obtained when wool fabric treated by the combination of H₂O₂ and Keratinase.The high degradation efficiency,low costs,and environment-friendly working conditions made keratinase as potential tools for textile industry.However,More research needed to be examined for its potential role in Shinkproofing.