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DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER

Engineering of a fungal laccase to develop a robust, versatile and highly-expressed biocatalyst for sustainable chemistry

 Uncategorized  Comments Off on Engineering of a fungal laccase to develop a robust, versatile and highly-expressed biocatalyst for sustainable chemistry
Sep 042019
 

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Engineering of a fungal laccase to develop a robust, versatile and highly-expressed biocatalyst for sustainable chemistry

Abstract

Fungal laccases can play an important role as biocatalysts in organic chemistry to replace chemical synthesis. In a previous work we synthesized conductive polyaniline using a high-redox potential laccase from our collection of recombinant fungal variants. Still, the oxidation of aniline is hindered by the reaction conditions (low pH and presence of anionic surfactants). Thus, we tackle here the directed evolution of the enzyme asisted by computational simulation aiming at improving aniline oxidation at the required polymerization conditions while maintaining the enzyme´s substrate promiscuity. Simultaneously, its secretion by the host used for the engineering (Saccharomyces cerevisiae) was enhanced. Then, the improved laccase variant was overproduced in the industrial host Aspergillus oryzae and assayed for one‐pot synthesis of polyaniline and naphtol-derived dyes whose textile dyeing properties were verified in an industrial environment. Finally, modification of its C-terminal tail further enhanced laccase stability by flexibilization of the region. The resulting biocatalyst displays noticeable stability at high temperature and extreme pH while shows improved kcat values on the different substrates tested. Moreover, it is remarkably produced in S. cerevisiae at rates not formerly reported in the literature. These facts, together with the overexpression in A. oryzae opens new scenarios for its further development and application.

Enzyme production and purification Laccase was produced by S. cerevisiae 1 L-flask cultures and purified as described before.5 Laccase activity in the culture was measured spectrophotometrically with 3 mM ABTS in 100 mM citrate-phosphate buffer, pH 3 by the increase of Absorbance 418 nm (ε418 = 36000 M−1 cm−1). One activity unit (U) was defined as the amount of enzyme needed to transform 1 µmol substrate/minute. To estimate enzyme production, enzyme concentration of a purified laccase variant was measured by the A280 (Nanodrop 2000, Thermofisher, USA) and the specific activity (U/mg) was calculated and used to deduce the mg of enzyme/l obtained in the culture. Enzyme characterization All characterization assays were performed with purified enzymes.

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https://pubs.rsc.org/en/content/articlepdf/2019/gc/c9gc02475a

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Enzymatic resolution of antidepressant drug precursors in an undergraduate laboratory

 drugs, spectroscopy, SYNTHESIS  Comments Off on Enzymatic resolution of antidepressant drug precursors in an undergraduate laboratory
Apr 012015
 

Enzymatic resolution of antidepressant drug precursors in an undergraduate laboratory

EducaçãoQuim. Nova 2015, 38(2), 285-287

Enzymatic resolution of antidepressant drug precursors in an undergraduate laboratory

Luís M. R. SolanoI; Nuno M. T. LourençoII,*
This paper describes a multi-step chemo-enzymatic synthesis of antidepressant drug precursors.

http://dx.doi.org/10.5935/0100-4042.20140306

Publicado online: novembro 13, 2014
Quim. Nova, Vol. 38, No. 2, 285-287, 2015
Educação http://dx.doi.org/10.5935/0100-4042.20140306
*e-mail: nmtl@tecnico.ulisboa.pt
ENZYMATIC RESOLUTION OF ANTIDEPRESSANT DRUG PRECURSORS IN AN UNDERGRADUATE LABORATORY
Luís M. R. Solanoa and Nuno M. T. Lourençob,* a Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal b Departamento de Bioengenharia, Instituto de Biotecnologia e Bioengenharia, Instituto Superior Técnico, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal
Recebido em 07/07/2014; aceito em 17/09/2014; publicado na web em 13/11/2014
The use of biocatalysts in synthetic chemistry is a conventional methodology for preparing enantiomerically enriched compounds. Despite this fact, the number of experiments in chemical teaching laboratories that demonstrate the potential of enzymes in synthetic organic chemistry is limited. We describe a laboratory experiment in which students synthesized a chiral secondary alcohol that can be used in the preparation of antidepressant drugs. This experiment was conducted by individual students as part of a Drug Synthesis course held at the Pharmacy Faculty, Lisbon University. This laboratory experiment requires six laboratory periods, each lasting four hours. During the first four laboratory periods, students synthesized and characterized a racemic ester using nuclear magnetic resonance spectroscopy and gas chromatography. During the last two laboratory periods, they performed enzymatic hydrolysis resolution of the racemic ester using Candida antarctica lipase B to yield enantiomerically enriched secondary alcohol. Students successfully prepared the racemic ester with a 70%-81% overall yield in three steps. The enzymatic hydrolysis afforded (R)- secondary alcohol with good enantioselectivity (90%–95%) and reasonable yields (10%–19%). In these experiments, students were exposed to theoretical and practical concepts of aromatic acylation, ketone reduction, esterification, and enzymatic hydrolysis. Keywords: sec-alcohols; esters; lípase; enantiomers; resolution.
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