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Laccases are multi-copper containing oxidases (EC, widely distributed in fungi, higher plants and bacteria. Laccase catalyses the oxidation of phenols, polyphenols and anilines by one-electron abstraction, with the concomitant reduction of oxygen to water in a four-electron transfer process. In the presence of small redox mediators, laccase offers(More)
Laccases are an interesting group of multi copper enzymes, which have received much attention of researchers in last decades due to their ability to oxidize both phenolic and non-phenolic lignin related compounds as well as highly recalcitrant environmental pollutants. This makes these biocatalysts very useful for their application in several(More)
An extracellular beta-fructofuranosidase from the yeast Xanthophyllomyces dendrorhous was characterized biochemically, molecularly, and phylogenetically. This enzyme is a glycoprotein with an estimated molecular mass of 160 kDa, of which the N-linked carbohydrate accounts for 60% of the total mass. It displays optimum activity at pH 5.0 to 6.5, and its(More)
The β-fructofuranosidase Xd-INV from the yeast Xanthophyllomyces dendrorhous is the largest microbial enzyme producing neo-fructooligosaccharides (neo-FOS) known to date. It mainly synthesizes neokestose and neonystose, oligosaccharides with potentially improved prebiotic properties. The Xd-INV gene comprises an open reading frame of 1995 bp, which encodes(More)
The generation of diversity for directed protein evolution experiments shows an important bottleneck in the in vitro random mutagenesis protocols. Most of them are biased towards specific changes that eventually confer a predicted and conservative mutational spectrum, limiting the exploration of the vast protein space. The current work describes a simple(More)
Reliable screening methods are being demanded by biocatalysts' engineers, especially when some features such as activity or stability are targets to improve under non-natural conditions (i.e., in the presence of organic solvents). The current work describes a protocol for the design of a fungal laccase-expressed in Saccharomyces cerevisiae-highly active in(More)
The in vitro fermentation of several purified galacto-oligosaccharides (GOS), specifically the trisaccharides 4′-galactosyl-lactose and 6′-galactosyl-lactose and a mixture of the disaccharides 6-galactobiose and allolactose, was carried out. The bifidogenic effect of GOS at 1 % (w/v) was studied in a pH-controlled batch culture fermentation system(More)
BACKGROUND The ascomycete Ophiostoma piceae produces a sterol esterase (OPE) with high affinity towards p-nitrophenol, glycerol and sterol esters. Its hydrolytic activity on natural mixtures of triglycerides and sterol esters has been proposed for pitch biocontrol in paper industry since these compounds produce important economic losses during paper pulp(More)
Sugar syrup and molasses from beet processing containing 620 and 570 mg/mL sucrose, respectively, were assayed as low-cost and available substrates for the enzymatic synthesis of fructo-oligosaccharides (FOSs). A commercial pectinase (Pectinex Ultra SP-L, from Aspergillus aculeatus) characterized by the presence of a transfructosylating activity was used as(More)
Antioxidants protect cells against the effects of harmful free radicals and play an important role in preventing many human diseases (e.g. cancer, atherosclerosis, neurodegeneration, inflammatory disorders, etc.) and aging itself. In addition, antioxidant molecules are employed to prevent unsaturated oil products from becoming rancid during storage and thus(More)