N-butanol production from fermentation of sugar cane bagasse hemicellulosic hydrolysate with cell immobilization

• Grant number: 18/25925-0
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): March 01, 2019
• Effective date (End): January 31, 2020
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Adriano Pinto Mariano
• Grantee: Gabriela Matias
• Home Institution: Faculdade de Engenharia Química (FEQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 15/20630-4 - Biorefinery development integrated to a bioethanol sugar cane plant with zero CO2 emission: routes to convert renewable resources to bio-products and bio-electricity, AP.TEM

Abstract

The butanol production by fermentation is limited to the low economic competitiveness associated with high prices of raw materials, energy inefficiency, low yield, and productivity. The use of sugarcane bagasse hemicellulosic hydrolysate (C5 sugars, main xylose) and molasses as raw materials, are low-cost options and there is not competition for raw materials of second-generation ethanol production because the C5 sugars are not fermentable by the microorganismSaccharomyces cerevisiae. One option that is being studied for this problem, it is the conversion of the hemicellulosic hydrolysate to butanol by ABE fermentation (acetone/butanol/ethanol). However, this alternative also has its own challenges. The hemicellulosic hydrolysate is diluted (~20 gL-1 xylose) and contains microbial inhibitors generated on pretreatment, thus preventing the efficient conversion of xylose. The bacteria of the genus clostridium have the ability to naturally metabolize the present pentoses and make ABE fermentation more viable in terms of productivity. Therefore, the main objective of this scientific initiation project is to increase the conversion efficiency of the sugarcane bagasse hemicellulosic hydrolysate(non-detoxified) into n-butanol. To achieve this purpose, it will be developed a fermentation strategy that combining three elements: mixing of hemicellulosic hydrolysate with molasses, passive cell immobilization using the sugarcane bagasse as cell carrier and fed-batch operation. Thus, the low yield and productivity can be solved by evaluating the conversion of the hemicellulose hydrolysate to butanol and applying cell immobilization techniques that promote high cell concentration.