A novel keratinase from Bacillus tequilensis strain Q7 with promising potential for the leather bating process.

The present paper reports on the purification and characterization of an extracellular keratinase (KERQ7) newly purified from Bacillus tequilensis Q7. Pure protein was obtained after ammonium sulfate fractionation (30-60%), followed by Mono S Sepharose cation-exchange chromatography. MALDI-TOF/MS analysis revealed that the purified enzyme was a monomer with a molecular mass of 28,355.

Probing the crucial role of Leu31 and Thr33 of the Bacillus pumilus CBS alkaline protease in substrate recognition and enzymatic depilation of animal hide.

The sapB gene, encoding Bacillus pumilus CBS protease, and seven mutated genes (sapB-L31I, sapB-T33S, sapB-N99Y, sapB-L31I/T33S, sapB-L31I/N99Y, sapB-T33S/N99Y, and sapB-L31I/T33S/N99Y) were overexpressed in protease-deficient Bacillus subtilis DB430 and purified to homogeneity. SAPB-N99Y and rSAPB displayed the highest levels of keratinolytic activity, hydrolysis efficiency, and enzymatic depilation. Interestingly, and at the semi-industrial scale, rSAPB efficiently removed the hair of goat hides within a short time interval of 8 h, thus offering a promising opportunity for the attainment of a lime and sulphide-free depilation process.

Biochemical and molecular characterization of a serine keratinase from Brevibacillus brevis US575 with promising keratin-biodegradation and hide-dehairing activities.

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) loads in the effluent.