title: Purification and properties of Amycolatopsis mediterranei DSM 43304 lipase and its potential in flavour ester synthesis.
abstract: An extracellular thermostable lipase from Amycolatopsis mediterranei DSM 43304 has been purified to homogeneity using ammonium sulphate precipitation followed by anion exchange chromatography and hydrophobic interaction chromatography. This protocol resulted in a 398-fold purification with 36% final recovery. The purified A. mediterranei DSM 43304 lipase (AML) has an apparent molecular mass of 33 kDa. The N-terminal sequence, AANPYERGPDPTTASIEATR, showed highest similarity to a lipase from Streptomyces exfoliatus. The values of K(m)(app) and V(max)(app) for p-nitrophenyl palmitate (p-NPP) at the optimal temperature (60°C) and pH (8.0) were 0.099±0.010 mM and 2.53±0.06 mmol/min mg, respectively. The purified AML displayed significant activity towards a range of short and long chain triglyceride substrates and p-nitrophenyl esters. Hydrolysis of glycerol ester bonds occurred non-specifically. The purified AML displayed significant stability in the presence of organic solvents (40%, v/v) and catalyzed the synthesis of the flavour ester isoamyl acetate in free and immobilized states.
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland. dheeman@gmail.com
authors.forename: Dharmendra S
authors.initials: DS
authors.lastname: Dheeman
authors.forename: Gary T M
authors.initials: GT
authors.lastname: Henehan
authors.forename: Jesus M
authors.initials: JM
authors.lastname: Frías
mesh_terms: D000192:Actinomycetales / Q000201:enzymology*; D000595:Amino Acid Sequence; D004789:Enzyme Activation; D004795:Enzyme Stability; D004951:Esterification; D004952:Esters; D008049:Lipase / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D000439:Pentanols / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D004952:Esters; D000439:Pentanols; D008049:Lipase; C020377:isoamyl acetate