title: Effect of the inducers veratryl alcohol, Xylidine, and ligninosulphonates on activity and thermal stability and inactivation kinetics of laccase from Trametes versicolor.
abstract: Laccase production from Trametes versicolor was improved in the presence of the inducers ligninosulphonates, veratryl alcohol, and xylidine respectively two-, four-, and eightfold. The thermal inactivation of the produced laccase, after partial purification with ammonium sulfate was kinetically investigated at various temperatures (60-70 °C) and pH values (3.5, 4.5, and 5.5). The inactivation process followed first-order kinetics for all conditions tested, except for veratryl alcohol, for which a constant activity level was observed at the end of the inactivation, also after first-order decay. Enzyme thermostability was affected by the type of inducer used in the culture medium for the production of laccase and also by the pH of incubation mixture. Generally, laccase stability increased with pH increment, being more stable at pH 5.5, except with xylidine. At pHs 4.5 and 5.5, the three inducers significantly increased laccase thermal stability, with the higher effect being observed for pH 5.5 and ligninosulphonates, where increment of half-life times ranged from 3- to 20-fold, depending on the temperature.
authors.affiliation: Produtos Naturais e Agro-alimentares, Unit Research of Química Orgânica, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Portugal.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Saraiva
authors.forename: Ana P M
authors.initials: AP
authors.lastname: Tavares
authors.forename: Ana M R B
authors.initials: AM
authors.lastname: Xavier
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D000814:Aniline Compounds / Q000494:pharmacology*; D001592:Benzyl Alcohols / Q000494:pharmacology*; D011232:Chemical Precipitation; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D042845:Laccase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008031:Lignin / Q000494:pharmacology*; D013696:Temperature; D055454:Trametes / Q000201:enzymology*
chemical_list: D000814:Aniline Compounds; D001592:Benzyl Alcohols; D008031:Lignin; D042845:Laccase; C042197:veratryl alcohol; D000645:Ammonium Sulfate