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Abstract: A Thermoalkalophilic amylase was produced from an environmental bacterial isolate. The enzyme was then immobilized through its amino groups onto the epoxy rings of magnetic poly glycidyl methacrylate [m-poly (GMA)] beads. The free enzyme was active within a large pH range, between 7 and 12 and displayed the optimum activity at 95°C and pH 10. The immobilization appeared to increase the stability of the enzyme as its bound form showed optimum activity at 105°C and pH 11.0. Kinetic studies demonstrated that immobilized enzyme had higher K m and lower V max values. The activity of the free and bound enzyme was determined, at 37°C and pH 10.0 and pH 11.0, respectively, in the presence of various organic solvents and detergents (5%, v/v). Results obtained indicated that detergents, sodium dodecyl sulfate (SDS) and TritonX-100, caused six fold increase and that various organic solvents also increased the activity of the amylase. [Copyright &y& Elsevier]

A thermostable metalloprotease, produced from an environmental strain of Candida kefyr 41 PSB, was purified 16 fold with a 60% yield by cold ethanol precipitation and affinity chromatography (bentonite-acrylamide-cysteine microcomposite). The purified enzyme appeared as a single protein band at 43 kDa. Its optimum pH and temperature points were found to be 7.0 and 105 °C, respectively. K m and V max values of the enzyme were determined to be 3.5 mg/mL and 4.4 μmol mL −1 min −1 , 1.65 mg/mL and 6.1 μmol mL −1 min −1 , using casein and gelatine as the substrates, respectively. The activity was inhibited by using ethylenediamine tetraacetic acid (EDTA), indicating that the enzyme was a metalloprotease. Stability of the enzyme was investigated by using thermodynamic and kinetic parameters. The thermal inactivation profile of the enzyme conformed to the first order kinetics. The half life of the enzyme at 95, 105, 115, 125 and 135 °C was 1310, 610, 220, 150, and 86 min, respectively. [ABSTRACT FROM AUTHOR]