The impact of lignin from sugar cane bagasse upon enzymatic hydrolysis of cellulose: biophysical interactions and molecular scale lignin structures

• Grant number: 12/08610-0
• Support type: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): July 01, 2012
• Effective date (End): November 30, 2012
• Field of knowledge: Engineering - Chemical Engineering
• Principal researcher: Roberto de Campos Giordano
• Grantee: Ursula Fabiola Rodríguez Zúniga
• Supervisor abroad: Claus Felby
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Research place: University of Copenhagen, Denmark
• Associated to the scholarship: 10/15072-9 - Advanced techniques for chemical and structural characterization of biomass applied to the industrial production of ethanol from sugarcane bagasse, BP.PD

Abstract

Lignin is a highly complex branched biopolymer of phenolic nature. During lignocellulose pretreatments it was proposed that lignin flows and coalesces to form redeposit structures which act as physical barrier for enzymatic hydrolysis action. Though it was identified that lignin may adsorb enzymes it is not clear if the inactivation mechanism is reversible on lignin surfaces and how is the performance of a less condensed lignin from a tropical lignocellulose biomass such as sugarcane bagasse. In the present work lignin isolates will be prepared from different pretreated sugarcane bagasse. The isolates will be analyzed compositionally by traditional wet methods, ATR-IR spectrometry and SEM and AFM microscopy. Enzymatic hydrolysis and protein adsorption studies will be made to assess the action of non-hydrolytic enzymatic activities in this particular lignin and then there will be related to characterization data. This study will be complemented by the research of the recent discovery oxidative enzymes (GH61) that enhance cellulose hydrolysis. We will research the effect of oxidative activity in a commercial enzyme mix (Cellic CTec2) upon overall hydrolysis and the formation of oxidized products such as gluconic acid. The substrates for the experiments will use sugarcane bagasse pretreated by various methods rating different lignin ratios. Experiments will be done at high solids loadings using a lignocellulosic substrate simulating commercially relevant conditions. (AU)