Optimization of a chemically defined medium composition for acetylxylan esterase production in recombinant Escherichia coli

• Grant number: 20/04429-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2020
• End date: July 31, 2021
• Field of knowledge: Engineering - Chemical Engineering
• Principal Investigator: Eutimio Gustavo Fernández Núñez
• Grantee: Ismael Elvis da Silva
• Host Institution: Escola de Artes, Ciências e Humanidades (EACH). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

To ensure that the next generations will be able to meet their needs, it is necessary to move to a bioeconomy model, in which there are a devaluation of fossil fuels and the development of less CO2 emitting processes. In this sense, research projects have been seeking to optimize the enzymatic hydrolysis of lignocellulosic biomass. To achieve this goal, the synergistic action of several enzymes is necessary, including those capable of degrading cellulose, hemicellulose, and lignin. The enzyme acetylxylan esterase acts on the O-2 and/or O-3 acetylated xylan units, removing the acetyl group from the hemicellulose side chains and releasing acetic acid. Once the xylan is deacetylated, the action of the other enzymes is possible without steric impediment, facilitating the complete degradation of hemicellulose. In this project a recombinant Escherichia coli will be used to produce acetylxylan esterase in Erlenmeyer flasks as a culture system. A complete three-level factorial design (32) will be carried out to determine the best combination of glucose (10-25 g/L) and ammonium sulfate (1-5 g/L) to guarantee the maximum production of the enzyme in a chemically defined medium. To accomplish this objective, Biochemical Engineering and Chemometrics approaches for bioprocess development will be applied. The data will be processed in software such as Design Expert and Matlab, willing to create a statistical model which represents the expression of acetylxylan esterase in the culture system adopted, considering kinetic factors and productivity. The expected results would allow to design experiments in bench-top bioreactors and then sketch a scale-up to this bioprocess, which will be possibly useful to enhance the production of ethanol 2G in Brazil. (AU)