Analysis of the pattern of acetylation and feruloylation of sugar cane arabinoxylan

• Grant number: 13/25396-4
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2014
• End date: July 31, 2016
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Marco Aurelio Silva Tine
• Grantee: Marco Aurelio Silva Tine
• Host Institution: Instituto de Botânica. Secretaria de Meio Ambiente, Infraestrutura e Logística (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Camila Caldana ; Helaine Carrer

Abstract

Brazil is the second largest producer of ethanol in the world, but there is still a large demand to be met. The best perspective for the increase of production is the second generation ethanol, produced from the digestion and fermentation of the cell wall components of the bagasse. The development of this technology is directly related to the understanding of the sugar cane cell wall structure. Despite the importance of the plant for all the ethanol productive chain, many aspects of the structure of the cell wall are not clear yet. In particular, the ramification pattern with acetate and ferulic acid in the main hemicellulose of the sugar cane: the arabinoxylan. This lack of knowledge is, in great part, due to the typical analysis method, which involves the fractionation of the wall with NaOH, hydrolyzing the ether linkage of these ramifications. This project proposes the study of the changes in the structure of the arabinoxylan caused by the change in the expression of the Cafeoyl O-Methyl transferase (COMT). In particular, the variations in the abundance of ferulic acid and acetylations, since this gene is essential for the synthesis of ferulic acid and lignin subunits. It was already demonstrated that the available mutants have reduction in the contend of lignin in the wall (to different degrees), but the structure of the hemicellulose in unknown. The literature shows that changes in one component of the wall usually leads to unexpected changes in other components, in a steady state that keeps the functionality of the wall. To achieve the objective, a new technique will be developed for the extraction of arabinoxylan in its native structure. The extracted arabinoxylan will be analysed by enzymatic digestion with xylanase and the olygosaccharides produced will have their structure analysed by chromatography and mass spectrometry. The combined use of these techniques will allow both the identification of the structure of these oligosaccharides and the development of fingerprinting techniques that will be used to characterization of the arabinoxylan. (AU)