The present Thesis deals with the development of enzymatic treatments (based on the use of laccases in the presence of redox mediators) aimed at the removal/modification of the lignin and/or lipids present in lignocellulosic materials of industrial interest, in order to achieve a more efficient and rational use of these materials for the production of both, cellulose and second generation biofuels (bioethanol). The importance of lipids in the raw materials lays in the fact that they are responsible for the formation of the so-called pitch deposits during pulp and paper manufacturing, drastically reducing the quality of the final product and producing important economic losses. Moreover, the content, composition and structure of the lignin have a significant effect on the delignification process of the lignocellulose, affecting both the cooking and bleaching processes (during the production of cellulose) or the enzymatic saccharification (during the production of bioethanol).

Este trabajo se ha llevado a cabo en el Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS) del Consejo Superior de Investigaciones Científicas (CSIC). Ha sido financiado por los proyectos europeos: “Optimized pre-treatment of fast growing woody and nonwoody Brazilian crops by detailed characterisation of chemical changes produced in the lignin-carbohydrate matrix” (LIGNODECO, KBBE-2009-3-244362), “Novel and more robust fungal peroxidases as industrial biocatalyst” (PEROXICATS, KBBE-2010-4-265397) y “Optimized oxidoreductases for medium and large scale industrial biotransformation” (INDOX, KBBE-2013-7-613549), por el proyecto del Plan Nacional “Desarrollo de pretratamientos enzimáticos optimizados para la deconstrucción de materiales lignocelulósicos madereros y no-madereros” (LIGNOCELL, AGL2011-25379), y por el proyecto del CSIC “Cultivos lignocelulósicos de crecimiento rápido: composición química y aprovechamiento industrial” (2010-40E-075).

The present Thesis includes the following sections: I) a general introduction about lignocellulosic materials, their composition, their industrial interests, the processes used for the production of cellulose pulp and second generation biofuel, as well as the main problems originated by their constituents and some biotechnological solutions to address them; II) the objectives pursued in the Thesis; III) a detailed description of the selected materials and the analytical methods used; IV) the overall results obtained and their discussion; V) the cited references; VI) the scientific publications; and VII) the conclusions.

Peer reviewed