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Microbial & Enzyme Technology

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The research activities are in the field of Molecular Biotechnology aiming at the eco-efficient use of natural resources, the set-up of new bioremediation processes, and the production of bio-based products.

 

 

Lígia O. Martins
Professor Auxiliar Convidado
PhD 1994 in Biotechnology , UTL, IST

Phone (+351) 214469534 | Extension 1534
lmartins@itqb.unl.pt

 

Research Interests

Research in our laboratory involves the selection, characterization and engineering of promising microorganisms and enzymes for environmental and industrial applications.

We are pioneers in the structural and functional characterisation of bacterial laccases which are key ligninolytic enzymes. We contributed to the understanding of their redox properties and were the first to propose a comprehensive mechanism of the reduction of dioxygen based in x-ray crystal, mutagenesis, spectroscopic and kinetic studies. We studied the mechanisms of copper incorporation into these enzymes and are able to overproduce full copper loaded enzymes in the reductive cytoplasm of bacteria. We elucidated the laccase mechanisms involved in the oxidation of synthetic dyes and engineered an Escherichia coli strain coproducing CotA laccase from Bacillus subtilis and PpAzoR an azoreductase from Pseudomonas putida MET94 that synergistically degrade and detoxify dye-containing model wastewaters. The competitive routes involved in laccase-mediator systems were assessed using a multidisciplinary approach involving enzymology, electrochemistry, MS and NMR as well as the enzymatic synthesis of coloured bioproducts with potential impact in the cosmetic and dye industries. Recently we have focused on bacterial dye-decolourising peroxidases, novel enzymes that show very promising properties for several biotechnological applications.
 


Group Members

    • Vânia Brissos, Post-doc
    •  Zhenghia Chen, Post-doc
    • Sónia Mendes, PhD student
    • Diogo Tavares, Master student
    •  Joaquim Madeira, Master student
    • Bruna Pinto, Master student
    •  Susana Proença, Project student
       


Selected Publications

  1. Sousa AC, Oliveira MC, Martins LO and Robalo MP. 2014. Towards the rational biosynthesis of substituted phenazines and phenoxazinones by laccases. Green Chem. 16: 4127–4136
  2. Brissos, V, Gonçalves, N, Melo, EP, Martins LO. 2014. Improving kinetic or thermodynamic stability of an azoreductase by directed evolution. PLoS One. 9: e87209
  3. Santos, A, Mendes, S, Brissos, V, Martins, LO 2014. New dye decolourising peroxidases from Bacillus subtilis and Pseudomonas putida: towards biotechnological applications. Appl. Microbiol. Biotechnol. 98:2053-2065 


Laboratory's Website

For further information please visit the laboratory's website

  

Tecnologia Microbiana e Enzimática (PT)

O nosso laboratório estuda microrganismos e enzimas com potencial para aplicações biotecnológicas (ambientais e industriais). Estudamos a correlação entre a estrutura de enzimas, nomeadamente lacases bacterianas, com a sua função. Para isso são utilizadas várias metodologias que envolvem técnicas de Microbiologia, Biologia Molecular, Bioquímica e Biofísica. Também temos colaborações estabelecidas com outros grupos o que nos permite realizar uma caracterização o mais completa possível das enzimas que estudamos. Por técnicas de mutagénese dirigida estudamos quais as zonas das proteínas importantes para a catálise uma vez que estudamos o efeito da substituição de resíduos de aminoácidos específicos nas caracteristicas das enzimas. Eventualmente, esperamos que algumas das substituições que fazemos possam gerar enzimas mais eficazes para utilizações biotecnológicas. Tendo este objectivo em mente, estamos neste momento a optimizar técnicas de Evolução Dirigida, em que utilizamos estratégias de mutagénese aleatória seguidas de rastreio para propriedades importantes sob o ponto de vista biotecnológico (por exemplo, maior estabilidade e utilização de substratos não naturais), de forma a encontrar biocatalisadores robustos e melhorados para utilização industrial.

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