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Molecular investigation of new xylose isomerases for application to lignocellulosic materials fermentation

Grant number: 18/02865-2
Support type:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): August 01, 2018
Effective date (End): February 28, 2022
Field of knowledge:Biological Sciences - Biochemistry
Principal Investigator:Leticia Maria Zanphorlin
Grantee:Renan Yuji Miyamoto
Home Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). Campinas , SP, Brazil
Associated research grant:15/26982-0 - Exploring novel strategies for depolymerization of plant cell-wall polysaccharides: from structure, function and rational design of glycosyl hydrolases to biological implications and potential biotechnological applications, AP.TEM

Abstract

To become the second-generation ethanol production economically viable, it is crucial the hemicellulose fraction utilization, composed by pentoses, mainly xylose. Xylose, obtained by saccharification of hemicellulosic structures, is currently underappreciated, chiefly because the industrial yeasts, Saccharomyces cerevisiae, can not metabolize this sugar to produce second generation ethanol (E2G). Thus, a strategy to improve xylose utilization by S. cerevisiae consists in isomerization of xylose to xylulose by enzymes named Xylose Isomerase (XylA). However, most of XylA presents optimum pH and temperatures incompatible with physiological condition of S. cerevisiae, besides present very inefficient expression levels. In this scenario, this project aims the investigation of new xylose isomerase that was previously selected by in silico approach, to operate in fermentation processes with industrial yeast Saccharomyces cerevisiae. The XylA will be expressed in E. coli BL21 and will be evaluated using a multidisciplinary approach that includes biochemical and classical biophysical assays, as well as cristalization, and solve the tertiary structure, besides ex-situ Simultaneous Isomerization and Fermentation (SIF). In the end, the XylA that presents more efficient and compatible with fermentation conditions will be had it codon optimized and transformed in S. cerevisiae. The Genetically Modified Microrganism (GMO) Saccharomyces cerevisiae developed will be evaluated against fermentation assays with xylose and then compared with the one already used industrially. (AU)