Atypical laccases from the white-rot fungus Pleurotus ostreatus and their application for the treatment of industrial coloured effluents
Fecha
2006Versión
Acceso abierto / Sarbide irekia
Tipo
Contribución a congreso / Biltzarrerako ekarpena
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
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nodoi-noplumx
|
Resumen
White-rot fungi are the most efficient decomposers of lignocellulose because
of their capability to synthesize the relevant hydrolytic (cellulases and hemicellulases)
and oxidative (laccases, lignin-peroxidases and Mn-peroxidases)
extracellular enzymes required to degrade the major components of substrates
(cellulose, hemicellulose, and lignin) into low-molecular-weight compounds
that can be ...
[++]
White-rot fungi are the most efficient decomposers of lignocellulose because
of their capability to synthesize the relevant hydrolytic (cellulases and hemicellulases)
and oxidative (laccases, lignin-peroxidases and Mn-peroxidases)
extracellular enzymes required to degrade the major components of substrates
(cellulose, hemicellulose, and lignin) into low-molecular-weight compounds
that can be assimilated in fungal nutrition [1]. Recently, extensive research
on these fungi has been conducted with the aim of isolating new
organisms able to secrete new enzymes with capability to be used in industrial
applications, such as bioremediation of polluted soils and industrial
waste-waters, biobleaching and biopulping in pulp and paper industries, textile
and food industries, etc. Fungal laccases (benzenediol: oxygen oxidoreductases; EC1.10.3.2) are
ligninolytic enzymes that have been isolated from various fungi [2]. They belong
to the class of the blue oxidases containing 4 copper atoms/molecule
distributed in three different copper binding sites [3, 4]. The type-1 site is
responsible for the intense blue colour of the enzyme due to a maximum absorbance
at 605 nm; the type-2 site does not exhibit signals in the visible absorbance
spectrum; and the type-3 site incorporates two copper centres and
is responsible for a band near 330 nm. All these copper ions are involved in
the catalytic mechanism. Laccases reduce oxygen to water and simultaneously
perform a one electron oxidation of aromatic substrates (polyphenols,
methoxysubstituted monophenols, aromatic amines, etc.). These enzymes are
present in multiple isoforms, depending on the fungal species and environmental
growth conditions [5, 6]. [--]
Materias
Laccases,
Pleorotus ostreatus,
Industrial applications
Editor
Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Publicado en
Antonio G. Pisabarro and Lucía Ramírez (eds.): VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI). Pamplona: Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2006.
Notas
Comunicación presentada al VI Meeting on Genetics and Cellular Biology of Basidiomycetes (GCBB-VI), organizado por y celebrado en la Universidad Pública de Navarra el 3-6 de junio de 2005.
Entidades Financiadoras
This work was supported by grants from the Ministero dell’Università e della
Ricerca Scientifica (Progetti di Rilevante Interesse Nazionale, PRIN) and
from EC FP6 Project SOPHIED (NMP2-CT-2004-505899).