Resumo

ABREU, Heber et al. Proposta de Modificação da Biossíntese da Lignina como Estratégia para Correcção de Defeitos em Madeiras. Silva Lus. [online]. 2003, vol.11, n.2, pp.217-225. ISSN 0870-6352.

Lignin, which corresponds to approximately 15 to 35% of the dry weight of the wood, works as a binding agent for cell wall, and could easily be modified by genetic engineering or by other experimental techniques, affecting the activity of the PAL, 4CL, C4H, C3H, OMT, F5H, CCR, CAD enzymes, which mediate reactions before lignin polymerization. Such techniques will allow plants to change syringyl lignin, which is more fragile (IMF higher), into guaiacyl lignin, which is much more rigid (IMF lower). This opens new perspectives for the control of cracks as observed in Eucalyptus wood after harvest. Considering that the strength of the cell wall depends on the structural lignin organization, the biosynthesis of modified lignin in terms of molecular architecture within the cell wall opens up new possibilities in the search for solutions for greater applications of wood in industry. In this way, the scope of this article is to propose solution to solve some natural wood defects, suggesting changes in the biochemical lignin pathway which transforms Guaiacyl/Syringyl lignin into Coumaryl/Guaiacyl lignin.

Palavras-chave : lignin; biosynthesis; biotechnology; enzymes.

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