Characterization of an extracellular alkaline serine protease from marine Engyodontium album BTMFS10

An alkaline protease from marine Engyodontium album was characterized for its physicochemical properties towards evaluation of its suitability for potential industrial applications. Molecular mass of the enzyme by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) analysis was calculated as 28.6 kDa. Isoelectric focusing yielded pI of 3-4. Enzyme inhibition by phenylmethylsulfonyl fluoride (PMSF) and aprotinin confirmed the serine protease nature of the enzyme. K (m), V (max), and K (cat) of the enzyme were 4.727 x 10⁻² mg/ml, 394.68 U, and 4.2175 x 10⁻² s⁻¹, respectively. Enzyme was noted to be active over a broad range of pH (6-12) and temperature (15-65 °C), with maximum activity at pH 11 and 60 °C. CaCl₂ (1 mM), starch (1%), and sucrose (1%) imparted thermal stability at 65 °C. Hg²⁺, Cu²⁺, Fe³⁺, Zn²⁺, Cd⁺, and Al³⁺ inhibited enzyme activity, while 1 mM Co²⁺ enhanced enzyme activity. Reducing agents enhanced enzyme activity at lower concentrations. The enzyme showed considerable storage stability, and retained its activity in the presence of hydrocarbons, natural oils, surfactants, and most of the organic solvents tested. Results indicate that the marine protease holds potential for use in the detergent industry and for varied applications.