Full text
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| Author(s): |
Letícia Marrone de Souza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-06-23 |
| Examining board members: |
Paulo Mazzafera;
Marcos Silveira Buckeridge;
Ladaslav Sodek
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| Advisor: | Paulo Mazzafera |
| Abstract | |
Sugarcane is the leading source of sucrose for first generation bioethanol production and more recently an important source of lignocellulosic biomass for second-generation ethanol production, obtained from cellulose deposited in plant cell walls. Lignin, a complex aromatic heteropolymer present in the secondary wall of plant cells, is the main factor conferring recalcitrance in lignocellulosic material and a major obstacle encountered by biorefineries for the viable production of second-generation ethanol. This biopolymer is formed by oxidative combinatorial coupling of mainly three p-hydroxycinnamyl alcohol monomers: p-coumaryl, coniferyl and sinapyl alcohols. When incorporated into the lignin polymer, these monomers are called p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units, respectively, and are connected by different types of covalent bonds. With the knowledge about content and composition of lignin, and the types of linkages between S, G, and H units that affect the recalcitrance of the cell wall, this study aimed at gaining knowledge regarding lignin composition and biosynthesis in four sugarcane genotypes grown under field conditions in two localities in the State of São Paulo. The genotypes were previously analyzed for lignin content and were contrasting for this characteristic: IACSP04-028 and IACSP04-053 with lower lignin content (± 4%) and IACSP04-691 and IACSP04-015, with higher lignin content (± 8 %). The cortex and medulla regions of the sugarcane stem, at two growth stages, could be distinguished by lignin content in the same way that the composition of lignin (S/G ratio) showed significant differences among these tissues. Oligomer profiling identified twelve phenolic compounds among aldehydes, dimers and trimers showing locality effect between genotypes. The relative expression patterns of nineteen genes encoding enzymes from the lignin biosynthetic pathway indicated a high degree of complexity when correlated with molecular and biochemical data. The results presented here provide an important additional knowledge about lignin biosynthesis in sugarcane, which can contribute to further study and manipulation of genes involved in the biosynthesis process of this polymer in order to optimize the production of lignocellulosic ethanol using sugarcane biomass as raw material (AU) | |
| FAPESP's process: | 12/23187-6 - LIGNIN METABOLISM IN FOUR SUGARCANE GENOTYPES GROWN IN FIELD CONDITIONS |
| Grantee: | Letícia Marrone de Souza |
| Support Opportunities: | Scholarships in Brazil - Master |