Biotechnology for Lignocellulosic Biomass

The scientific objectives of our group include:

1) Providing knowledge on the biological decay of plant biomass with special emphasis on the transformation and degradation of lignin by fungi, a key process for C recycling in nature and the complete exploitation of plant biomass as raw material in the Lignocellulose Biorefineries, as an alternative to the use of fossil resources.

2) Promoting the use of these organisms and their enzymes (improved in the lab by molecular biology, protein engineering, computational design and synthetic biology techniques) for the industrial conversion of renewable plant biomass into bio-based chemicals and/or materials, including the synthesis of bioplastics.

3) Contributing in this way to the concept of Circular (Bio)economy through more sustainable, efficient and clean industrial processes (and with lower carbon footprint) in which organic waste (agricultural, forestry or industrial) is not generated or is used, as well as to the valorization and recycling of oil-derived plastic polymers.

To achieve the above objectives, we develop basic and applied research lines. The former focus on unveiling the composition and understanding the behaviour of the enzymatic machinery responsible for the transformation of lignocellulose by fungi specialized in its degradation (projects CSP15-1609 from DOE-JGI and GenoBioref from BIO2017). To do this, we carry out multi-omic studies, including secretomic, transcriptomic and comparative genomic analyses of a wide variety of saprophytic fungal species, complemented with chemical analyses of degraded substrates. These studies are key for the discovery of new enzymes. We are particularly interested in oxidoreductases involved in the biodegradation of the lignin polymer and other aromatic compounds of great biotechnological interest. Of special interest are also the peroxygenases secreted by saprophytic fungi, homologous to (intracellular) P450s but phylogenetically unrelated. Both share the ability to selectively catalyze oxygenation reactions that are difficult to achieve by chemical means, but while P450s require auxiliary proteins and a source of reducing power, the fungal peroxygenases are self-sufficient and require only peroxide to be activated. This fact, together with their greater robustness as secreted enzymes, provides them a much higher biotechnological potential as selective biocatalysts in the chemical sector. Finally, the phylogenetic and evolutionary studies of all these enzymes, and the computational reconstruction and subsequent resurrection and characterization of ancestral enzymes, provide valuable information to understand the changes responsible for the properties of current enzymes and for the design of new tailor-made enzymes of industrial interest.

The applied research lines start from the heterologous expression of the most interesting extant or resurrected oxidoreductases from a biotechnological point of view. These studies focus on improving the enzyme properties or acquiring the new functionalities required (for each specific application) by means of directed evolution and/or rational design, as well as their use as biocatalysts in oxidative synthesis or degradation reactions of industrial interest, such as those investigated in the WoodZymes (https://woodzymes.eu), SusBind (https://susbind.eu), and FurEnPol (PLEC2021-007690) projects, led by our group. Our work in these projects focuses on enzymes of the (i) multicopper oxidase, (ii) heme-peroxidase, (iii) heme-peroxygenase, and (iv) flavo-oxidase types, and their use as biocatalysts in the conversion of plant materials in value-added compounds or in components of bio-based products, developing oxidation and oxyfunctionalization reactions of interest in Green Chemistry. The group also participates in the CSIC SusPlast Interdisciplinary Thematic Platform on "Sustainable Plastics for a Circular Economy", with the aim of contributing with biotechnological solutions to the production of bio-based plastics from renewable sources and the transformation and recycling of petroleum-derived polymers.

The activities carried out by our group are aligned with several of the global change challenges proposed in the CSIC 2025 Strategy. In this sense, we actively contribute to finding answers to scientific challenges with a high social impact, such as those included in the WoodZymes, SusBind and FurEnPol mentioned above. In the same way, our research work is reflected in patents and first-level high-impact international publications, as a result of interdisciplinary collaborations, which have allowed us to consolidate collaborations with national, European and American universities, research centers and companies.