1,721,018 research outputs found
Development of a biosensing platform based on a laccase-hydrophobin chimera
No full textA simple and stable immobilization of a laccase from Pleurotus ostreatus was obtained through genetic fusion with a self-assembling and adhesive class I hydrophobin. The chimera protein was expressed in Pichia pastoris and secreted into the culture medium. The crude culture supernatant was directly used for coatings of polystyrene multi-well plates without additional treatments, a procedure that resulted in a less time-consuming and chemicals reduction. Furthermore, the gene fusion yielded a positive effect with respect to the wild-type recombinant enzyme in terms of both immobilization and stability. The multi-well plate with the immobilized chimera was used to develop an optical biosensor to monitor two phenolic compounds: L-DOPA ((S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid) and caffeic acid (3-(3,4-dihydroxyphenyl)-2-propenoic acid); the estimation of which is a matter of interest in the pharmaceutics and food field. The method was based on the use of the analytes as competing inhibitors of the laccase-mediated ABTS oxidation. The main advantages of the developed biosensor are the ease of preparation, the use of small sample volumes, and the simultaneous analysis of multiple samples on a single platform
Last Advances in Synthesis of Added Value Compounds and Materials by LaccasemediatedBiocatalysis
No full textLaccases represent versatile catalysts being able to oxidize a wide range of aromatic substrates and are susceptible of several
industrial applications based on both oxidative degradation reactions and synthetic chemistry. The range of laccase based synthetic reactions
is extremely wide. Laccases are able to catalyze transformation of antibiotics based on both -lactams functionalization and
phtalides functionalization. These enzymes can also catalyze derivatization of amino acids to obtain metabolically stable amino acid analogues,
maximizing biological response while minimizing toxicity, thus representing an useful system for drug development. Biomolecules
having antioxidative and anticancer activity can also be produced by laccase-mediated reactions of flavonoids oxidative coupling
and phenoxazinones synthesis. Application of laccases to production of new derivatives of the hormones resveratrol, 17ß-estradiol,
totarol and isoeugenol and oligomerization products of substituted imidazoles was also reported, with applications for pharmacological
purposes due to hormonal activity of the products. The enzymatic preparation of aromatic polymeric materials by the action of laccases
represents a viable and non-toxic alternative to the usual formaldehyde-based chemical production of these compounds and it has been
reported for several substrates such as 2,6-dimethylphenol, 4-hydroxybenzoic acid derivatives, 3,5-dimethoxy-4-hydroxybenzoic acid and
3,5-dimethyl-4-hydroxybenzoic acid, aniline and acrylamide. Moreover, laccase-mediated biografting of phenols or certain other types of
low-molecular weight compounds provides a method for tailoring the surface of lignocellulosics or for adhesion enhancement in binderless
wood boards under mild conditions and usually without harmful solvents. Laccase-mediated modification of lignocellulosic materials
is accomplished through two main routes: coupling of low-molecular weight compounds onto lignocellulosic materials and laccase mediated
cross-linking of lignin molecules in situ. Depending on the choice of laccase substrate, properties such as improved strength properties,
increased antimicrobial resistance, or hydrophilicity/ hydrophobicity can be imparted to lignocellulosic materials
How to enjoy laccases
No full textAn analysis of the scientific literature published in
the last 10 years reveals a constant growth of laccase applicative
research in several industrial fields followed by the
publication of a great number of patents. The Green Chemistry
journal devoted the cover of its September 2014 issue to a
laccase as greener alternative for chemical oxidation. This
indicates that laccase ‘‘never-ending story’’ has found a new
promising trend within the constant search for efficient
(bio)catalysts able tomeet the 12 green chemistry principles.A
survey of ancient and cutting-edge uses of laccase in different
industrial sectors is offered in this review with the aim both to
underline their potential and to provide inspiration for new
ones. Applications in textile and food fields have been deeply
described, as well as examples concerning polymer synthesis
and laccase-catalysed grafting. Recent applications in pharmaceutical
and cosmetic industry have also been reviewed
Transcriptional analysis of Pleurotus ostreatus laccase genes
No full textFungal laccases (p-diphenol:oxygen oxidoreductase; EC 1.10.3.2) are multi-copper-containing oxidases that catalyse the oxidation of a great variety of phenolic compounds and aromatic amines through simultaneous reduction of molecular oxygen to water. Fungi generally produce several laccase isoenzymes encoded by complex multi-gene families. The Pleurotus ostreatus genome encodes 11 putative laccase coding genes, and only six different laccase isoenzymes have been isolated and characterised so far.
Laccase expression was found to be regulated by culture conditions and developmental stages even if the redundancy of these genes still raises the question about their respective unctions in vivo. In this context, laccase transcript profiling analysis has been used to unravel the physiological role played by the different isoforms produced by P. ostreatus. Even if reported results depict a complex picture of the transcriptional responses exhibited by the analysed laccase genes, they were allowed to speculate on the isoform role in vivo. Among the produced laccases, LACC10 (POXC) seems to play a major role during vegetative growth, since its transcription is downregulated when the fungus starts the fructification process. Furthermore, a new tessera has been added to the puzzling mosaic of the heterodimeric laccase LACC2 (POXA3). LACC2 small subunit seems to play an additional physiological role during fructification, beside that of LACC2 complex activation/stabilisation
Fungal laccases degradation of endocrine disrupting compounds
Full text linkOver the past decades, water pollution by trace organic compounds (ng/L) has become one of the key environmental issues in developed countries. This is the case of the emerging contaminants called endocrine disrupting compounds (EDCs). EDCs are a new class of environmental pollutants able to mimic or antagonize the effects of endogenous hormones, and are recently drawing scientific and public attention. Their widespread presence in the environment solicits the need of their removal from the contaminated sites. One promising approach to face this challenge consists in the use of enzymatic systems able to react with these molecules. Among the possible enzymes, oxidative enzymes are attracting increasing attention because of their versatility, the possibility to produce them on large scale, and to modify their properties. In this study five different EDCs were treated with four different fungal laccases, also in the presence of both synthetic and natural mediators. Mediators significantly increased the efficiency of the enzymatic treatment, promoting the degradation of substrates recalcitrant to laccase oxidation. The laccase showing the best performances was chosen to further investigate its oxidative capabilities against micropollutant mixtures. Improvement of enzyme performances in nonylphenol degradation rate was achieved through immobilization on glass beads
Identification of a new member of the dye-decolorizing peroxidase family from Pleurotus ostreatus
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