Optimization of cello-oligosaccharides production by enzymatic hydrolysis of pretreated sugarcane straw using cellulolytic and oxidative enzymes

Fernando Cesar Barbosa

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Author(s):	Fernando Cesar Barbosa Total Authors: 1
Document type:	Doctoral Thesis
Press:	Campinas, SP.
Institution:	Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos
Defense date:	2020-10-30
Examining board members:	Rosana Goldbeck; Telma Teixeira Franco; Marcelo Mendes Brandão; Fernando Segato; Eliana Setsuko Kamimura
Advisor:	Rosana Goldbeck
Abstract
Cello-oligosaccharides (COS) are oligomers with 2 to 6 ?-1,4-linked glucose units, with potential applications in the food/feed and bioenergy industrial sectors. It has been demonstrated that COS are important functional oligosaccharides because it is able to support the growth of different probiotic strains and, it offers several advantages for fermentative processes when used as substrate in place of glucose to produce bioethanol. Several approaches for COS production optimization have been reported, mainly regarding suitable enzymes and combinations thereof. With this premise, this project has the main goal of optimize the production of COS by enzymatic hydrolysis of pretreated sugarcane straw via heterologous expression of cellulolytic and oxidative enzymes. After the enzymes selection and expression in Pichia pastoris, the optimized the combination of the endoglucanases CaCel and CcCel9m, the lytic polysaccharide monooxygenase (LPMO) TrCel61A, the cellobiose dehydrogenase (CDH) NcCDHIIa, with lactose and copper as additives, produced 60.49 mg of COS per g of pretreated sugarcane straw without glucose production. Moreover, under the conditions evaluated in this project, this work also concluded the possible lignin modification/reallocation, the removal of hemicellulose and in consequence its interaction with lignin, and the decrease in crystallinity index appeared to be the most effective characteristic obtained from the steam-explosion for COS production using the selected endoglucanase. Finally, early-stage techno-economic and life cycle assessment for cellopentaose production demonstrated that the upstream sector appeared to be the most relevant sector for both analyses. The assessment demonstrated a reduction between 6.34 and 18.23-fold in the unit production cost in comparison to cellopentaose current market selling price. Moreover, it was possible to observe an overall life cycle impact reduction between 16.2 and 19.9% comparing the baseline with the 3-fold scaled-up + 10% yield scenario. The results demonstrated that the development of a platform for cellopentaose production based on the developed process is feasible (AU)

FAPESP's process:	17/16159-0 - Optimization of cello-oligosaccharides production by enzymatic hydrolysis of sugarcane straw via heterologous expression of cellulolytic and oxidative enzymes
Grantee:	Fernando César Barbosa
Support Opportunities:	Scholarships in Brazil - Doctorate (Direct)

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