Microbial & Enzyme Technology
We want to contribute for the eco-efficient use of natural resources, the set-up of new bioremediation processes, and the production of bio-based products, through the use of microorganisms and enzymes.
Head of Laboratory
Professor Auxiliar Convidado PhD 1994 in Biotechnology , UTL, IST | Research InterestsGroup MembersSelected Publications | ||
Phone (+351) 214469534 | |
Research Interests
Research in our laboratory involves the selection, characterization, and engineering of promising microorganisms and enzymes for environmental and industrial applications.
For the last few years, we have been studying bacterial laccases, enzymes with high non-specific oxidation efficiency that do not require the addition of expensive cofactors, and instead use the readily available oxygen as electron acceptor. Documented applications of these enzymes include polymerization of phenols, functionalization of natural polymers, delignification, textile dye bleaching, effluent detoxification, transformation of antibiotics and steroids. More recently we have isolated a Pseudomona putida strain that shows a superior ability to degrade a range of structurally diverse azo dyes, and focuses on studies with the enzymes azoreductases and peroxidases, with potential interesting applications.
We have undertaken a multidisciplinary study to understand the molecular determinants of enzyme activity and stability, to identify the key biocatalyst structure-function features and to get insight into the catalysis reaction mechanisms. For example, through site directed mutagenesis we examined how replacing key amino acid residues affects enzyme properties. By elucidating important aspects of the stability and catalytic mechanism of laccases, we have highlighted the limitation of the traditional rational approaches for enzyme design. Our system for improving enzyme properties is therefore to resort to directed evolution techniques, followed by robotic high-throughput screening.
On the technological side, we have focused on the biodegradation of pollutants such as synthetic industrial colorants, namely azo and anthraquinonic dyes. From the 106 tons of synthetic dyes produced every year, over 10% is released in wastewaters, as stable organic xenobiotic. Resorting to biotechnology for the transformation of these dyes is both technically very attractive and, in the case of azoredutases and laccases, quite promising.
Within the concept of biorefinery we have recently begun investigating the enzymatic bioconversions of lignin, the recalcitrant biopolymer that gives wood its strength. In the carbon cycle, degradation of lignin is a limiting step and clean technologies to unlock lignin, and hence cellulose, as renewable sources of chemicals and fuels may show great importance in the future.
Group Members
- Vânia Brissos, Post-doc
- Zhenjia Chen, Post-doc
- Sónia Mendes, PhD student
- Tânia Rosado, PhD student
- Pedro Bernardo, BI student
- Nádia Gonçalves, MsC student
- Ana Filipa Santos, MsC student
Selected Publications
- Durão, P, Bento, I, Fernandes, AT, Melo, EP, Lindley, PF and Martins, LO. 2006. Perturbations of the T1 copper site in the CotA-laccase from Bacillus subtilis: structural, biochemical, enzymatic and stability studies. J Biol Inorg Chem 11:514-26.
- Durão, P, Chen, Z, Fernandes, AT, Hildebrandt, P, Murgida, DH, Todorovic, S, Pereira, MM, Melo, EP and Martins, LO. 2008. Copper incorporation into recombinant CotA-laccase from Bacillus subtilis - Characterization of fully Cu-loaded enzymes. J Biol Inorg Chem 13:183-93
Rosado, T, Bernardo, P, Koci, K, Coelho, AV, Robalo, MP, Martins, LO. 2012. Methyl syringate: an efficient phenolic mediator for bacterial and fungal laccases. Bioresour. Technol. 124:371-378
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.
