Biotechnology for lignocellulosic biomass

Novel oxidoreductases for lignocellulose biorefineries: Expression, characterization, engineering and evaluation in lignin transformation

Lignocellulose biorefineries seek the integral use of plant biomass to produce chemicals, fuels and materials. A significant percentage of this biomass is represented by lignin, an aromatic polymer whose valorization is essential for the viability of these biorefineries. Chemical methods currently used for lignin depolymerization are not suitable for production of added value compounds and it is necessary to develop new processes to transform this polymer. Ligninolytic fungi are a good alternative to chemical methods because of their ability to depolymerize lignin in nature. To do this, they use oxidoreductases (peroxidases and laccases).

The proposed TFM will focus on the study of peroxidases of biotechnological interest. First, the DNA sequences encoding these enzymes will be identified in fungal genomes of ligninolytic Agaricales recently sequenced by the U.S. Department of Energy Joint Genome Institute (DOE JGI) in the frame of a project coordinated by our group. Then, they will be expressed (in prokaryotic hosts), purified and characterized (stability and catalytic properties). Finally, their biotechnological potential will be evaluated in oxidation reactions of technical lignins (lignosulfonates). If necessary, the operational properties of these enzymes will be improved by rational design based on the analysis of structural models generated in silico.