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Understanding the complex structure of lignin from sugarcane bagasse and the impact on the antioxidant capacity and its biochemical conversion into value added products

Grant number: 15/07008-2
Support type:Scholarships abroad - Research Internship - Doctorate
Effective date (Start): July 01, 2015
Effective date (End): May 31, 2016
Field of knowledge:Biological Sciences - Biochemistry - Chemistry of Macromolecules
Principal researcher:Fábio Márcio Squina
Grantee:Lívia Beatriz Brenelli de Paiva
Supervisor abroad: Claus Felby
Home Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovações (Brasil). Campinas , SP, Brazil
Research place: University of Copenhagen, Denmark  
Associated to the scholarship:13/03061-0 - Characterization and antioxidant capacity of fractions of lignin extracted from sugarcane bagasse, BP.DR

Abstract

In the near future the sugar platform, based on the biorefinery concept, will biochemically convert of all components from plant cell wall biomass into value added products. Lignin from sugarcane bagasse is a by-product from biomass-based industries and recognized as efficient antioxidants due to its particular aromatic structure. However, lignin is untapped biopolymer in biomass bioconversion technologies. Some possible strategies for lignin valorization are focused into selective functionalization of this organic polymer in order to improve compatibility in composites, as well as, oxidative depolymerization to get polyfunctional monomeric compounds to be used as feed-stocks in polymer industry. According to previous study from our group, lignin derived from steam exploded bagasse was successfully fractionated by decreasing pH of black liquor from 12 to 2 with sulfuric acid. The acidification process of lignin resulted on reduced-polydispersity and low-molecular-weight preparations with high free-radical scavenging capacity at low pH. During first steps of acidification from pH 10 to 6), our biophysical data (based on SAXS) suggest that large lignin molecules were formed, macromolecules showing sphere shape with not exposed surface-accessible phenolic hydroxyl groups, which are not effective to donate electrons or protons and stabilize the radicals species. However, more detailed studies are necessary to understand how lignin structures affect antioxidant efficiency for low pH lignin-preparations (pH2 and 4). Redox enzymes, such as Peroxygenases (EC 1.11.2.1) and laccases (EC 1.10.3.2) show potential to produce added-value products from lignin. Enzymes that catalyze oxygen-transfer reactions are of great interest for chemical synthesis since they work selectively and under mild ambient conditions. However, there is a knowledge gap about the effects of these enzymes on isolated lignins. For this BEP proposal, we plan to employ peroxygenases (POXs) and lacase mediator system (LMS) to modify property and structure of homogeneous lignins preparation, followed by comprehensive structural studies of lignin changes, such as the identification and quantification of radical reaction intermediates by electron spin resonance (ESR) spectrometry. Spectrometric studies with low-molecular-weight preparations of lignin obtained at low pH will also be carried out. These studies can provide basis for development of biochemical routes to overcoming the inherent heterogeneity of lignin-enriched streams and allow for the production of higher-value and sustainable commodities. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
BRENELLI, LIVIA B.; PERSINOTI, GABRIELA F.; FRANCO CAIRO, JOAO PAULO L.; LIBERATO, MARCELO V.; GONCALVES, THIAGO AUGUSTO; OTERO, IGOR V. R.; MAINARDI, PEDRO H.; FELBY, CLAUS; SETTE, LARA D.; SQUINA, FABIO M. Novel redox-active enzymes for ligninolytic applications revealed from multiomics analyses of Peniophora sp. CBMAI 1063, a laccase hyper-producer strain. SCIENTIFIC REPORTS, v. 9, NOV 26 2019. Web of Science Citations: 0.
BRENELLI, LIVIA; SQUINA, FABIO M.; FELBY, CLAUS; CANNELLA, DAVID. Laccase-derived lignin compounds boost cellulose oxidative enzymes AA9. BIOTECHNOLOGY FOR BIOFUELS, v. 11, JAN 17 2018. Web of Science Citations: 25.

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