18 documents found, page 1 of 2
A wide array of lignin-related phenolics are oxidized by an evolved bacterial d...
Silva, Diogo; Sousa, Ana Catarina; Robalo, Maria Paula; Martins, Lígia O.Lignin is the second most abundant natural polymer next to cellulose and by far the largest renewable source of aromatic compounds on the planet. Dye-decolourising peroxidases (DyPs) are biocatalysts with immense potential in lignocellulose biorefineries to valorize emerging lignin building blocks for environmentally friendly chemicals and materials. This work investigates the catalytic potential of the enginee...
Environmentally Friendly Degradation and Detoxification of Rifampicin by a Bact...
Durao, Paulo; Kis, Peter; Chelo, Ivo M; Ventura, M. Rita; Martins, Lígia O.Antibiotics are micropollutants accumulating in our rivers and wastewaters, potentially leading to bacterial antibiotic resistance, a worldwide problem to which there is no current solution. Here, we have developed an environmentally friendly two-step process to transform the antibiotic rifampicin (RIF) into non-antimicrobial compounds. The process involves an enzymatic oxidation step by the bacterial CotA-lacc...
A wide array of lignin-related phenolics are oxidized by an evolved bacterial d...
Silva, Diogo; Sousa, Ana Catarina; Robalo, M.P.; Martins, Lígia O.Lignin is the second most abundant natural polymer next to cellulose and by far the largest renewable source of aromatic compounds on the planet. Dye-decolourising peroxidases (DyPs) are biocatalysts with immense potential in lignocellulose biorefineries to valorize emerging lignin building blocks for environmentally friendly chemicals and materials. This work investigates the catalytic potential of the enginee...
Rationally guided improvement of NOV1 Dioxygenase for the conversion of lignin-...
De Simone, Mario; Alvigini, Laura; Alonso-Cotchico, Lur; Brissos, Vânia; Caroli, Jonatan; Lucas, Maria Fátima; Monza, Emanuele; Melo, EduardoBiocatalysis is a key tool in both green chemistry and biorefinery fields. NOV1 is a dioxygenase that catalyzes the one-step, coenzyme-free oxidation of isoeugenol into vanillin and holds enormous biotechnological potential for the complete valorization of lignin as a sustainable starting material for biobased chemicals, polymers, and materials. This study integrates computational, kinetic, structural, and biop...
Unveiling molecular details behind improved activity at neutral to alkaline pH ...
Borges, Patrícia T.; Silva, Diogo; Silva, Tomás F.D.; Brissos, Vânia; Cañellas, Marina; Lucas, Maria Fátima; Masgrau, Laura; Melo, EduardoDyP-type peroxidases (DyPs) are microbial enzymes that catalyze the oxidation of a wide range of substrates, including synthetic dyes, lignin-derived compounds, and metals, such as Mn2+ and Fe2+, and have enormous biotechnological potential in biorefineries. However, many questions on the molecular basis of enzyme function and stability remain unanswered. In this work, high-resolution structures of PpDyP wild-t...
Laccases: versatile biocatalysts for the synthesis of heterocyclic cores
Sousa, Ana Catarina; Martins, Lígia O.; Robalo, M. PaulaLaccases are multicopper oxidases that have shown a great potential in various biotechnological and green chemistry processes mainly due to their high relative non-specific oxidation of phenols, arylamines and some inorganic metals, and their high redox potentials that can span from 500 to 800 mV vs. SHE. Other advantages of laccases include the use of readily available oxygen as a second substrate, the formati...
Wasteful azo dyes as a source of biologically active building blocks
Fernandes, Ana; Pinto, Bruna; Bonardo, Lorenzo; Royo, Beatriz; Robalo, M. Paula; Martins, Lígia O.In this work, an environment-friendly enzymatic strategy was developed for the valorisation of dye-containing wastewaters. We set up biocatalytic processes for the conversion of azo dyes representative of the main classes used in the textile industry into valuable aromatic compounds: aromatic amines, phenoxazinones, phenazines, and naphthoquinones. First, purified preparations of PpAzoR azoreductase efficiently...
Bacterial laccases: some recent advances and applications
Martins, Lígia O.; Melo, Eduardo P.; Sanchez-Amat, Antonio; Robalo, Maria PaulaLaccases belong to the large family of multi-copper oxidases (MCOs) that couple the one-electron oxidation of substrates with the four-electron reduction of molecular oxygen to water. Because of their high relative non-specific oxidation capacity particularly on phenols and aromatic amines as well as the lack of requirement for expensive organic cofactors, they have found application in a large number of biotec...
Synthesis of Substituted 4-Arylamine-1,2-naphthoquinones in One-Pot Reactions U...
Sousa, Ana Catarina; Santos, Iolanda; Piedade, M. Fatima M.; Martins, Lígia O.; Robalo, M. PaulaAn efficient and environmentally benign biocatalytic strategy for the synthesis of substituted 4-arylamino-1,2-naphthoquinones was developed, through a cross-coupling reaction in which the 1,2-naphthoquinone nucleus, formed in the biocatalytic process mediated by CotA-laccase from Bacillus subtilis, is the key synthetic intermediate. Electrochemical data and kinetic parameters were determined revealing a signif...
Synthesis of azobenzene dyes mediated by cotA laccase
Sousa, Ana Catarina; Baptista, Sara R.; Martins, Lígia O.; Robalo, Maria PaulaAn eco-friendly protocol for the synthesis of azobenzene dyes by oxidative coupling of primary aromatic amines is reported. As efficient biocatalytic systems, CotA laccase and CotA laccase/ABTS (2,2’-azinobis(3-ethylbenzo-thiazoline-6-sulfonic acid)) enablethe oxidation of various substituted anilines, in aqueous medium, ambient atmosphere and under mild reaction conditions of pH and temperature. A series of az...