BIOCONVERSION OF BAMBOO TO BIOETHANOL USING THE TWO-STAGE ORGANOSOLV AND ALKALI PRETREATMENT

Zhiqiang Li, Zehui Jiang, Benhua Fei, Xing'e Liu, Yan Yu

Abstract


Bamboo’s ability to grow on nutrient-poor soils, with little requirement of silvicultural management, easy harvesting characteristics, vegetative propagation, fast growth, and a host of other desirable characteristics, make it a good candidate as an energy crop. Energy crops are cultivated solely for use as sources of energy through their conversion into alcohols. This study set out to determine the potential of moso bamboo to be used in the two-stage organosolv and alkali pretreatment for the production of bioethanol. Moso bamboo contains 63.3% (w/w) holocellulose and can serve as a low-cost feedstock for bioethanol production. After organosolv pretreatment (2% w/w H2SO4 in 75% w/w ethanol, 160 °C for 30 min), the bamboo was further delignified through pretreatment of sodium hydroxide (10% and 20% w/w) or calcium hydroxide (10% w/w), which resulted in about 96.5% (NaOH) and 85.7% (Ca(OH)2) lignin removal. The enzymatic hydrolysis of delignified cellulosic bamboo substrate with cellulase (15 FPU/g glucan) and β-glucosidase (30 IU/g glucan) showed 80.9% to 95.5% saccharification after 48 h incubation at 50 °C and pH 4.8. Fermentation of enzymatic hydrolysates with Saccharomyces cerevisiae resulted in about 89.1% to 92.0% of the corresponding theoretical ethanol yield after 24 h.

Keywords


Bamboo; Bioethanol; Two-stage pretreatment; Enzymatic hydrolysis; Fermentation

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