Cotreatment-assisted thermophilic fermentation: a potentially transformative approach for producing second generation ethanol at low cost

• Grant number: 15/25866-6
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2016
• End date: October 31, 2018
• Field of knowledge: Engineering - Chemical Engineering
• Principal Investigator: Sindelia Freitas Azzoni
• Grantee: Sindelia Freitas Azzoni
• Host Institution: Faculdade de Engenharia Química (FEQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated researchers: Antonio Maria Francisco Luiz Jose Bonomi ; Maria Teresa Borges Pimenta Barbosa ; Otavio Cavalett ; Tassia Lopes Junqueira

Abstract

We propose a potentially transformative new approach for overcoming the lignocellulose recalcitrance barrier. Instead of thermochemical pretreatment prior to biological processing, we propose physical disruption during biological processing - termed "cotreatment". Although milling is known to be too energy-intensive to be practical for pretreatment followed by fungal cellulase-mediated hydrolysis, several compounding factors suggest that energy requirements for cotreatment-enhanced microbial fermentation will be lower by two orders of magnitude. First-of-a-kind data supporting this concept demonstrate a) bacterial fermentation proceeds readily in the presence of physical disruption at an intensity sufficient to substantially increase lignocellulose solubilization, and b) high extents of solubilization comparable to conventional pretreatment. Preliminary economic analysis is presented indicating potential for far lower cost than conventional lignocellulose conversion, particularly at small scale. A research project is proposed with the primary goal of evaluating the feasibility of cotreatment-enhanced thermophilic fermentation for conversion of bagasse to ethanol, and a secondary goal of familiarizing Brazilian researchers with techniques for metabolic engineering of thermophilic anaerobes. The project will be a collaborative effort led by Dr. Sindelia Freitas Azzoni and Maria Teresa B. Pimenta of CTBE and Professor Lee Lynd of Dartmouth College in the USA, and will feature bidirectional visits. Task 1 involves comparison of mechanical disruption strategies carried out separately from fermentation, and Task 2 involves integrated fermentation and mechanical disruption. Technoeconomic analysis will be carried out in Task 3, considering Brazilian reality and comparing to first generation and conventional second generation ethanol production. Completion of the proposed project will evaluate a potentially transformative new biomass processing concept for application to sugar cane feedstocks, and will also establish a research collaboration between CTBE and a leading research group in the second generation field. (AU)