Cotreatment-assisted fermentation: metabolic engineering of C. thermocellum for improved ethanol titer

• Grant number: 16/23323-8
• Support Opportunities: Scholarships abroad - Research
• Effective date (Start): June 20, 2017
• Effective date (End): December 19, 2017
• Field of knowledge: Engineering - Chemical Engineering
• Principal Investigator: Sindelia Freitas Azzoni
• Grantee: Sindelia Freitas Azzoni
• Host Investigator: Lee Rybeck Lynd
• Host Institution: Faculdade de Engenharia Química (FEQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Research place: Dartmouth College, United States

Abstract

We propose a research project with the objective of generating new strains of C. thermocellum with better capacity to produce ethanol and familiarize the principal investigator with techniques of metabolic engineering of thermophilic bacteria. This proposal for a short-term research project is complementary to the regular research project approved by FAPESP (2015 / 25866-6), in which a new approach based on physical processing during biological processing (called Cotreatmento) is being investigated in order to overcome The recalcitrance of sugarcane bagasse for the production of 2G ethanol. Co-treatment is based on thermophilic and anaerobic biocatalysts such as Clostridium thermoellum. This bacterium presents a greater capacity to deconstruct the cellulosic biomass in comparison to the industrial fungal cellulase, however this bacterium presents low tolerance and yield in ethanol when compared to Saccharomyces cerevisae. To overcome this bottleneck, adaptive evolution and metabolic engineering strategies become necessary to develop this bacterial platform for second generation processes. Dr. Lynd's laboratory is a leader in the research of such strategies and has established the molecular biology tools necessary to implement metabolic engineering strategies in C. thermocellum. In this project, we propose the transfer of dehydrogenase enzymes with high NADP specificity as cofactor for an ethanol tolerant C. thermocellum strain to achieve ethanol titers compatible with the industrial metric (70-80 g / L). The new strains resulting from this stage will be used in the approved Fapesp project and the process performance using wild type and engineering strains will be compared to the light of the process performance parameters. (AU)