Immobilized aculeacin A acylase from Actinoplanes utahensis: characterization of a novel biocatalyst.
Aculeacin A acylase from Actinoplanes utahensis (AuAAC), an amidohydrolase able to catalyze the acyl moieties of antifungal echinocandin antibiotics, has been also described to efficiently hydrolyze penicillin V and natural aliphatic penicillins to yield 6-aminopenicillanic acid (6-APA). Hence, taking into account its potential use in the synthesis of beta-lactam antibiotics as well as antifungal echinocandins, the recombinant enzyme was covalently immobilized onto several epoxy-activated supports in order to obtain a robust biocatalyst to be used in industrial bioreactors. The best biocatalyst was obtained by attaching the enzyme on Sepabeads EC-EP5 where immobilized AuAAC was homogeneously distributed over the surface of this support as shown by confocal scanning microscopy. The obtained biocatalyst showed a specific enzymatic activity of 35.2 IU/g wet carrier in the hydrolysis of penicillin V at pH 8.0 and 45 degrees C. Temperature-activity profile of immobilized AuAAC at pH 8.0 showed that the highest activity for the hydrolysis of penicillin V was achieved at 75 degrees C, whereas pH-activity profile at 40 degrees C indicated the highest activity for the hydrolysis of penicillin V was achieved at pH 8.5. The immobilized enzyme was highly thermostable since it suffered no loss of activity at 65 degrees C and pH 8.0 during 360 min, and it could be recycled for at least 30 consecutive batch reactions at pH 8.0 and 45 degrees C without loss of catalytic activity. Substrate specificity of the derivative also showed its ability to efficiently hydrolyze other natural aliphatic penicillins such as penicillins K, F and dihydroF besides its own substrate aculeacin A. Such interesting properties of this immobilized biocatalyst could allow its exploitation in industrial preparation of beta-lactam antibiotics and echinocandins.
Hormigo
Daniel
D
Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, c/José Antonio Novais 2, 28040 Madrid, Spain.
de la Mata
Isabel
I
Acebal
Carmen
C
Arroyo
Miguel
M
D000581:Amidohydrolases / Q000378:metabolism*; D055162:Biocatalysis; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008848:Micromonosporaceae / Q000201:enzymology*; D018613:Microscopy, Confocal; D008863:Microspheres; D011994:Recombinant Proteins / Q000378:metabolism; D012995:Solubility; D013379:Substrate Specificity; D013696:Temperature
D004800:Enzymes, Immobilized; D011994:Recombinant Proteins; D000581:Amidohydrolases; C060671:aculeacin A acylase