title: Influence of cultivation conditions on the production of a thermostable extracellular lipase from Amycolatopsis mediterranei DSM 43304.
abstract: Among several lipase-producing actinomycete strains screened, Amycolatopsis mediterranei DSM 43304 was found to produce a thermostable, extracellular lipase. Culture conditions and nutrient source modification studies involving carbon sources, nitrogen sources, incubation temperature and medium pH were carried out. Lipase activity of 1.37 +/- 0.103 IU/ml of culture medium was obtained in 96 h at 28 degrees C and pH 7.5 using linseed oil and fructose as carbon sources and a combination of phytone peptone and yeast extract (5:1) as nitrogen sources. Under optimal culture conditions, the lipase activity was enhanced 12-fold with a twofold increase in lipase specific activity. The lipase showed maximum activity at 60 degrees C and pH 8.0. The enzyme was stable between pH 5.0 and 9.0 and temperatures up to 60 degrees C. Lipase activity was significantly enhanced by Fe(3+) and strongly inhibited by Hg(2+). Li(+), Mg(2+) and PMSF significantly reduced lipase activity, whereas other metal ions and effectors had no significant effect at 0.01 M concentration. A. mediterranei DSM 43304 lipase exhibited remarkable stability in the presence of a wide range of organic solvents at 25% (v/v) concentration for 24 h. These features render this novel lipase attractive for potential biotechnological applications in organic synthesis reactions.
authors.affiliation: Dublin Institute of Technology, Ireland.
authors.forename: Dharmendra S
authors.initials: DS
authors.lastname: Dheeman
authors.forename: Jesus M
authors.initials: JM
authors.lastname: Frias
authors.forename: Gary T M
authors.initials: GT
authors.lastname: Henehan
mesh_terms: D000192:Actinomycetales / Q000201:enzymology* / Q000254:growth & development*; D001431:Bacteriological Techniques; D001709:Biotechnology; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007700:Kinetics; D008049:Lipase / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012997:Solvents; D013045:Species Specificity; D013696:Temperature
chemical_list: D003470:Culture Media; D008670:Metals; D012997:Solvents; D002244:Carbon; D008049:Lipase; D009584:Nitrogen