Heterologous production, characterization and engineering of xylose isomerases for application in industrial fermentation of pentoses

• Grant number: 12/50056-0
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• Start date: March 01, 2013
• End date: March 31, 2015
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Agreement: Odebrecht Agroindustrial
• Principal Investigator: Igor Polikarpov
• Grantee: Igor Polikarpov
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Company: ETH Bioenergia
• City: São Carlos

Abstract

To make the production of second generation ethanol economically sustainable, it is essential to use the hemicellulose fraction of a biomass. The pentoses (P5) are not fermentable by common yeasts (Saccharomyces cerevisiae) used by the Brazilian industry. However, the xylose, a predominant fraction of P5, can be robustly converted by the action of xylose isomerases (Xls) on xylulose, which, in turn, is easily fermented by S. cerevisiae. In this project we are proposing to use modern tools of bioinformatics, genetics, large scale heterologous expression and Structural Molecular Biology/Biochemistry to identify, clone and express novel and potentially patentable Xls. We also aim to conduct their enzymatic studies and to change the Xls using protein engineering, to produce enzymes with high enzymatic activity and pH and temperature profiles compatible to the Brazilian industrial process conditions. In addition, immobilization of the optimized Xls to increase their lifetime and enable recycling is contemplated. We will pre-treat sugarcane bagasse to produce hemicellulosic hydrolyzate and conduct tests of simultaneous isomerization and fermentation of PS using commercial and industrial yeasts in the fermentation conditions close to ones established by Brazilian industry. It is important to note that this process does not use genetically modified organisms and is therefore easily scalable and usable under industrial conditions in Brazil. (AU)