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Improvement of enzymatic cocktails for sugar cane bagasse hydrolysis

Bianca Consorti Bussamra
Total Authors: 1
Document type: Master's Dissertation
Institution: Universidade Estadual de Campinas. Faculdade de Engenharia Química
Defense date:
Examining board members:
Francisco Maugeri Filho; Daniela Alves Ribeiro
Advisor: Sindelia Freitas Azzoni

The high cost of converting lignocellulose by enzymatic hydrolysis is a recurring problem that limits the production of bioethanol from a renewable and highly energetic source. Many factors affect the efficiency of the hydrolysis process, such as lignocellulosic substrates recalcitrance, pretreatment efficiency, enzyme ratios and loadings, inhibitors and non-productive adsorption. Furthermore, the high production costs of enzyme cocktails limit the enzyme loads, which contribute to technical and economic infeasibility of this process. Among the promising approaches to optimize hydrolysis reaction, there is the development of well-balanced cocktails involving different classes of enzymes. This project studies optimized enzyme cocktails for hydrolysis of pretreated sugar cane bagasse, where the enzymes were provided from both commercial source and microorganism cultivation (Trichoderma reesei and genetically modified Escherichia coli), followed by purification. Experimental simplex lattice design, followed by factorial design, were performed to optimize the enzymatic proportion. In both experiments, released glucose concentration was the result evaluated. To reduce reagent consumption, the hydrolysis was carried out in micro assays scale, which methodology was validated in this study. The optimized enzyme mixture, comprised of T. reesei fraction (80%), endoglucanase (10%) and ?-glucosydase (10%), was capable of converting 68,36% ± 5,57 of the cellulose present in hydrothermal pretreated bagasse, whereas commercial cocktails Cellic CTec H2 and Celluclast converted 70,43% ± 5,03 e 49,11% ± 0,49 of the same material, respectively, under the same conditions. Thus, the work reported here contributed to the identification of needed activities and their optimal proportions to improve T. reesei enzymatic cocktail, enhancing hydrothermal bagasse conversion. Protein purification strategies and analyses of experimental design and synergism can be used to obtain improved cocktails to hydrolyze other materials. (AU)

FAPESP's process: 12/23223-2 - Development of optimized enzyme cocktails for hydrolysis of sugar cane bagasse
Grantee:Bianca Consorti Bussamra
Support type: Scholarships in Brazil - Master