Blue and yellow laccases of ligninolytic fungi

Abstract

Extracellular laccases from submerged cultures of Coriolus versicolor BKM F-116, Panus tigrinus 8/18, Phlebia radiata 79 (ATCC 64658), Phlebia tremellosa 77-51 and from cultures of Pa. tigrinus 8/18, Ph. radiata 79 and Agaricus bisporus D-649 grown on wheat straw (solid-state fermentation) were purified. All enzymes from submerged cultures had a blue colour and characteristic absorption and EPR spectra. Laccases from the solid-state cultures were yellow-brown and had no typical blue oxidase spectra and also showed atypical EPR spectra. Comparison of N-terminal amino acid sequences of purified laccases showed high homology between blue and yellow-brown laccase forms. Formation of yellow laccases as a result of binding of lignin-derived molecules by enzyme protein is proposed.

Switching from blue to yellow: altering the spectral properties of a high redox potential laccase by directed evolution

“…Laccase-mediator systems have been exhaustively investigated, as they permit the oxidation of high redox potential compounds that cannot be oxidized by laccases alone (including lignin derivatives, recalcitrant dyes and PAHs) (Morozova et al 2007). Some fungal laccases produced in solid-phase cultures are yellow rather than the typical blue colour exhibited by the same laccases when produced in liquid cultures (Leontievsky et al 1997a(Leontievsky et al , 1997bPozdnyakova et al 2004Pozdnyakova et al , 2006a. In solid state fermentation of white-rot fungi using lignocellulosic materials (e.g., wheat straw containing lignin), a natural lignin-derived compound can modify the T1 Cu, switching from the oxidized resting state (Cu 2+ ) to the reduced state (Cu 1+ ), and thus quenching the Abs610T1Cu.…”

“…The A280/A610 ratio represents the combined absorbances of tryptophan and aromatic residues at 280 nm, divided by the absorbance of T1 Cu at 610 nm. Generally, blue laccases exhibit an A280/A610 ratio of ~20, while that of the yellow laccases ranges from 90 to 150 (Leontievsky et al 1997a;Pozdnyakova et al 2006a). Thus, the PM1L-wt is a blue-laccase, while the OB-1 mutant can be considered as yellow laccase, based on its T1 Cu spectral features ( Table 1).…”

“…In addition to blue laccases, several other laccases with distinct spectral characteristics have been described, such as yellow-brown laccases obtained from white-rot fungi under solid-state fermentation conditions. These laccases do not contain Abs610T1Cu, supposedly due to the presence of a putative natural mediator derived from lignin biodegradation located at the T1 Cu site (Leontievsky et al 1997a(Leontievsky et al , 1997bPozdnyakova et al 2004Pozdnyakova et al , 2006a). White laccases produced by different basidiomycete strains have also been described with a broad band at around 400 nm but no absorbance at 610 nm.…”

Laccases: a never-ending story

“…Yellow laccases have been purified from the phytopathogenic ascomycete G. graminis (oligomeric) [109] and from the basidiomycetes A. bisporus D621 (oligomeric) [116], Schizophyllum commune [129], Panus tigrinus [130], Phlebia radiata [131], P. ribis (oligomeric) [107], and P. ostreatus D1 [132,133]. Yellow laccases from P. tigrinus and P. ostreatus D1 are able to oxidize nonphenolic aromatic substrates in the absence of mediators, contrary to their blue counterparts [130,132,133].…”

White-Rot Fungi in Bioremediation

“…The ability of white-rot fungi to degrade a wide number of organopollutants is in part due to the action of nonspecific system (Paszczynski and Crawford 1995). Extracellular enzymes involved in the degradation of lignin and xenobiotics by white-rot fungi include several kinds of laccases (Leontievsky et al 1997;Thurston 1994), peroxidases (Camarero et al 1999), and oxidases producing H 2 O 2 (Guillén et al 1992;Volc et al 1996).…”