Excellent laundry detergent compatibility and high dehairing ability of the Bacillus pumilus CBS alkaline proteinase (SAPB)

The newly Tunisian soil-isolated bacterium, producing the alkaline proteinase termed SAPB that was already purified and characterized 1], was assigned as Bacillus pumilus CBS strain on the basis of biochemical properties and 16S rRNA gene sequencing. The maximum protease activity recorded after 24 h of incubation in an optimized medium at 37°C was 6,500 U/mL in shaking flask culture and 25,000 U/mL in fermentor. SAPB showed excellent stability and compatibility in laundry detergent retaining more than 98% of its initial activity after pre-incubation for 1 h at 40°C with Det, followed by OMO (97%), Dinol (94%), and Dixan (93%). Examination of various stained cloth pieces exhibited a remarkable efficiency in the removal of blood and chocolate stains. More interestingly, SAPB demonstrated powerful dehairing capabilities of hair removal from skin with minimal damage on the collagen and a nearly complete feather-degradation. Likewise, Bacillus pumilus CBS effectively degraded feather-meal (98.5%), chicken feather (92%), goat hair (80%), and bovine hair (68%) whereas sheep wool under went less degradation. Keratin-degradation resulted in sulfhdryl group formation (0.95∼3.91 μM).