Evaluation of an alternative pathway in Saccharomyces cerevisiae for the fermentation of cellodextrins using an modified energy balance

• Grant number: 12/25226-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2013
• End date: July 31, 2013
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Gonçalo Amarante Guimarães Pereira
• Grantee: Camila Cristina Juliato
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The dependence and the environmental impacts generated by the use of fossil fuels have been leading to the development of renewable energy sources. Ethanol arose as a solution and for this reason, a large number of studies have been searching for ways to maximize its production through the utilization of lignocellulosic biomass. However, this biomass has to be submitted through a pre-treatment and enzymatic hydrolysis so it can be properly converted to ethanol and these steps have really high costs. An alternative for cost reduction would be the application of microorganisms in the process that are capable of hydrolyzing and fermenting the compounds of the plant cell wall and producing ethanol as the final product. An industrial strain of Saccharomyces cerevisiae capable of fermenting cellodextrins was previously developed using genes that express cellodextrins transporters and intracellular ²-glucosidases, but the fermentation is still slow and in some cases impracticable. Thus the strategy of using an alternative metabolic pathway is highly promising. In this study, the development of the cellodextrins hydrolysis pathway will be compared with a phosphorylase pathway that results in higher leaps of ATP during the fermentation. With the superior energy balance of the new pathway, it its expected that the cellodextrins fermentation can become more efficient.(AU)