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Hidrólise enzimática de fibra de Caroá (Neoglaziovia variegata) visando à produção de nanocelulose e etanol

  • Gonçalves, Daniele Fernanda Chiarelli
Publication Date
Feb 03, 2016
Repositório Institucional UNESP
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The fiber of caroa plants has a high quantity of cellulose (≈ 65%) that can be used as a renewable energy source to produce nanocellulose and second-generation ethanol (2G). The aim of this research was to obtain nanocellulose and ethanol from caroa fiber using methods with minimal detrimental effects on the environment. Hydrothermal pretreatment trials (160, 170 and 180 oC) were carried out to remove the hemicellulose from caroa fiber. Based on the results, the pre-treated material at 160 °C in liquid hot water was delignified with 1% NaOH to obtain cellulose pulp. The organosolv method using water/ethanol ratio (50/50) at 180 oC was also studied. The efficiency of these processes was assessed by chemical characterization (content of cellulose, hemicellulose, and lignin) and by X-ray diffraction (XRD). The best yield of cellulose pulp was obtained from the pre-treated material using liquid hot water at 160 °C and delignified with 1% NaOH and was selected for further analysis. This material was submitted to thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). After the material was pretreated a second process, commercial endoglucanase E-CELTM, was used to hydrolyze the cellulosic pulp and to produce cellulose nanostructures. The nanocellulose obtained was characterized by atomic force microscopy (AFM). The AFM data shows the presence of nanocellulose crystal with aspect ratio of 16 ± 5. The residual of these materials was used for a new hydrolysis with the enzyme cocktail "Accellerase 1500" for release of fermentable sugars, which can be converted into ethanol. The concentration of glucose obtained after 72 h of reaction was 19,6 g L -1 and the concentration of ethanol after fermentation was 7,5 g L-1 . Therefore, caroa fibers are potential sources of nanocellulose and ethanol 2G.

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