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Enhancing saccharification of cassava stems by starch hydrolysis prior to pretreatment
- Martín, Carlos, Wei, Maogui, Xiong, Shaojun, Jönsson, Leif J.
- Industrial crops and products 2017 v.97 pp. 21-31
- Fourier transform infrared spectroscopy, X-ray diffraction, acetates, cassava, cellulose, enzymatic hydrolysis, hydrolysis, nuclear magnetic resonance spectroscopy, saccharification, starch, stems, sugars, sulfuric acid
- Chemical characterization of cassava stems from different origin revealed that glucans accounted for 54–63% of the dry weight, whereas 35–67% of these glucans consisted of starch. The cassava stems were subjected to a saccharification study including starch hydrolysis, pretreatment with either sulfuric acid or 1-ethyl-3-methylimidazolium acetate ([Emim]OAc), and enzymatic hydrolysis of cellulose. Starch hydrolysis prior to pretreatment decreased sugar degradation, improved enzymatic convertibility of cellulose, and increased overall glucan conversion. Glucan recovery after pretreatment of starch-free cassava stems (SFCS) was around 85%, but below 52% when the stems were pretreated under the same conditions without preparatory starch hydrolysis. The total amount of hydrolyzed glucan after cellulose hydrolysis was two-fold higher for pretreated SFCS than for directly pretreated stems. Pretreatment with [Emim]OAc resulted in 20% higher glucan conversion than pretreatment with acid. Pyrolysis-GC/MS, X-ray diffraction, CP/MAS 13C NMR and FTIR analyses revealed major differences between H2SO4- and [Emim]OAc-pretreated material.