A survey of elastase-producing bacteria and characteristics of the most potent producer, Priestia megaterium gasm32

by Ghadah A. AlShaikh-Mubarak, Essam Kotb, Amira H. Alabdalall, Munirah F. Aldayel

Ninety-one elastase-producing bacterial isolates were recovered from different localities of the Eastern Province of Saudi Arabia. Elastase from the best isolate Priestia megaterium gasm32, from luncheon samples was purified to electrophoretic homogeneity using DEAE-Sepharose CL-6B and Sephadex G-100 chromatographic techniques. The recovery was 17.7%, the purification fold was 11.7x, and the molecular mass was 30 kDa. Enzymatic activity was highly repressed by Ba²⁺ and almost completely lost by EDTA, but it was greatly stimulated by Cu²⁺ ions, suggesting a metalloprotease type. The enzyme was stable at 45°C and pH 6.0–10.0 for 2 hours. Ca²⁺ ions considerably enhanced the stability of the heat-treated enzyme. The V_max and K_m against the synthetic substrate elastin–Congo red were 6.03 mg/mL, and 8.82 U/mg, respectively. Interestingly, the enzyme showed potent antibacterial activity against many bacterial pathogens. Under SEM, most bacterial cells showed loss of integrity, damage, and perforation. SEM micrographs also showed a time-dependent gradual breakdown of elastin fibers exposed to elastase. After 3 hours, intact elastin fibers disappeared, leaving irregular pieces. Given these good features, this elastase may be a promising candidate for treating damaged skin fibers with the inhibition of contaminating bacteria.