Enhanced Production and Physicochemical Properties of a Commercially Viable Alkaline Protease from Bacillus amyloliquefaciens PFB-01
Folasade M. Olajuyigbe,
Olusola A. Ogunyewo.
Bacillus amyloliquefaciens PFB-01 produced extracellular alkaline protease (385.25 U/ml) under shake flask
conditions. Effects of process parameters such as cultivation period, pH, temperature, carbon and nitrogen sources on
protease production were investigated for optimization. Production of protease was optimized with 5.0% inoculum size in
culture medium (pH 8.0) incubated for 48 h at 37°C and 200 rpm. A combination of gelatin (0.75%) as nitrogen source
and glucose (0.5%) as carbon source gave maximum yield of protease (525.82U/mL) which was 138% increase over
enzyme yield in basal media. Soybean meal (0.75%) and glucose (0.5%) supported protease yield of 510.5 U/ml and
134% increase over basal media. The protease had optimum pH and temperature of 9.0 and 60 °C. Remarkably, it showed
60% residual activity after 60 min of incubation at 60 ºC in the absence of CaCl2. Protease activity was enhanced in the
presence of most organic solvents studied and most stable in the presence of 25% DMSO with residual activity of 93.7%.
The enzyme was compatible with the commercial detergents tested. Production of this protease in optimized media with
inexpensive and readily available soybean meal as alternative nitrogen source indicates that its production can be cost
effective for industrial applications. The physicochemical properties exhibited by the protease from B. amyloliquefaciens
PFB-01 make this enzyme commercially viable for exploitation in detergent industry and ester synthesis.
Keywords: Bacillus amyloliquefaciens PFB-01, commercially viable protease, optimization, production
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