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Optimization of acetylxylan esterase production from recombinant Escherichia coli cultivated in bioreactor

Grant number: 20/04429-5
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): August 01, 2020
Effective date (End): July 31, 2021
Field of knowledge:Engineering - Chemical Engineering
Principal Investigator:Eutimio Gustavo Fernández Núñez
Grantee:Ismael Elvis da Silva
Home 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 bioefficient, cyclical and 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. This project will focus only on the enzyme acetylxylan esterase, a carbohydrate esterase, which 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. A recombinant strain of Escherichia coli bacteria will be used to produce the enzyme in a bench-top bioreactor with mechanical agitation and aeration, carrying out a Box-Behnken experimental design to determine the best combination of oxygen (10-40 % air saturation), glucose ( 10-25 g/L) and ammonia (1-5 g/L) to guarantee maximum production of the enzyme. In order to accomplish this objective, Biochemical Engineering and Chemometrics tools for process development will be applied. The expected results would make possible to scaling up a relative complex bioprocess, increasing the aggregate value of agricultural residues (especially sugarcane bagasse) and, in some way, contribute to changing the national energy matrix, as the enzyme that is the object of this project incorporate enzymatic cocktails to be used in the production of second generation ethanol (2G). (AU)