Characterization of a novel protease fromBacillus cereusand evaluation of an eco-friendly hydrolysis of a brewery byproduct

Abstract

Proteases and proteolytic enzymes constitute one of the most important groups of enzymes and are attracting worldwide attention in attempts to exploit their physiological and biotechnological applications. In this study, partial purifications and biochemical and antimicrobial characterizations of a protease from Bacillus cereus spp., originally isolated from fermented cabbage, were carried out. The crude extract obtained after purification, involving ammonium sulphate precipitation and dialysis, was designated as a partially purified protease (PPP). The obtained PPP had a specific activity of 0.395-2.539 U/g at 32°C, with maximum activities for the fractions precipitated at 60 and 80% ammonium sulphate. The PPP activity ranged between 20 and 55°C, with an optimum temperature at 40°C. At 60°C, the PPP retained more than 30% of its activity. The optimum pH for the PPP was achieved at pH 9, indicating the alkaline source of the enzyme. Protease production was specifically dependent on the calcium concentration in the culture medium. Also the robustness of the protease on brewer's spent grain hydrolysis was demonstrated. This suggests a potential eco-friendly application of the enzyme. Finally, it was found that the PPP inhibited the growth of Escherichia coli O157:H7. This novel property of the PPP liberated by the B. cereus spp. could provide important future benefits to industry.

Evaluation and Optimization of Extracellular Digestive Enzymes from Bacillus spp. Isolated from Curds

“…Amongst, B. subtilis GS 1 showed the highest enzyme activity 157 ± 3.60 U/ml (p<0.05) at 37°C. Further, the optimum temperature was found to be 40°C and moreover, enzyme activity was stable in the temperature range 20 to 50°C for all the isolates and was in agreement with the report of Kotlar et al [31]. Further, pH 8 was optimum and the activity was stabilized between pH 6 and 9 for all the tested isolates.…”

Evaluation of brewer's spent grain as a substrate for production of hydrolytic enzymes by keratinolytic bacteria

“…The bacteria or proteases in the crude culture fluid were effectively capable of degradation and release of proteins from BSG. In addition, partially purified protease fractions were applied to release 2194 mg BSG mL −1 at maximum …”

Brazilian artisanal ripened cheeses as sources of proteolytic lactic acid bacteria capable of reducing cow milk allergy

“…; Kotlar et al . ). In contrast, the media containing low amounts of free amino acids may boost the induction of proteases (Hebert et al .…”