title: Random mutants of a Pleurotus ostreatus laccase as new biocatalysts for industrial effluents bioremediation.
abstract: OBJECTIVE
  To select better performing laccase variants among the 2300 randomly mutated variants of Pleurotus ostreatus POXA1b laccase to develop improved laccase-based biocatalysts.
  
  
  RESULTS
  Screening of collections of 2300 randomly mutated variants of POXA1b was performed by assaying activity towards the phenolic substrate 2,6-dimethoxyphenol. Two new variants endowed with higher enzyme activity than the wild-type laccase were characterized, and their ability to decolourize industrial dyes with complex trisazo-, polyazo- and stilbene-type structures, in the absence of mediators, was demonstrated. One of the mutants (2L4A) was also proved to be highly stable at both acidic and alkaline pH values (displaying a half-life of around 1 month at the pH levels of both 5 and 10).
  
  
  CONCLUSIONS
  In comparison with the wild-type laccase, the new selected 2L4A mutant shows a significant increase in stability at acidic pH, whilst storing its high stability at alkaline pH. This variant also represents a more versatile enzyme with respect to both the variety of xenobiotics degraded and the operative conditions.
  
  
  CONCLUSIONS
  This work represents the first example of improvement of a basidiomycete laccase for industrial effluents bioremediation by directed evolution.
authors.affiliation:  Department of Organic Chemistry and Biochemistry, University of Naples 'Federico II', Complesso Universitario Monte S. Angelo, via Cintia, Naples, Italy.| School of Biotechnological Sciences, University of Naples 'Federico II', Naples, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Miele
authors.affiliation:  Department of Organic Chemistry and Biochemistry, University of Naples 'Federico II', Complesso Universitario Monte S. Angelo, via Cintia, Naples, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Giardina
authors.affiliation:  Department of Organic Chemistry and Biochemistry, University of Naples 'Federico II', Complesso Universitario Monte S. Angelo, via Cintia, Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sannia
authors.affiliation:  Department of Organic Chemistry and Biochemistry, University of Naples 'Federico II', Complesso Universitario Monte S. Angelo, via Cintia, Naples, Italy.| School of Biotechnological Sciences, University of Naples 'Federico II', Naples, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Faraco
mesh_terms: D001673:Biodegradation, Environmental; D004396:Coloring Agents / Q000378:metabolism; D019020:Directed Molecular Evolution; D005656:Fungal Proteins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D042845:Laccase / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D020076:Pleurotus / Q000201:enzymology* / Q000235:genetics; D055550:Protein Stability; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D004396:Coloring Agents; D005656:Fungal Proteins; D011748:Pyrogallol; C010120:pyrogallol 1,3-dimethyl ether; D042845:Laccase