Enhanced enzymatic hydrolysis of poplar bark by combined use of gamma ray and dilute acid for bioethanol production

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2012-08, Vol.81 (8), p.1003-1007
• Main Authors: Chung, Byung Yeoup, Lee, Jae Taek, Bai, Hyoung-Woo, Kim, Ung-Jin, Bae, Hyeun-Jong, Gon Wi, Seung, Cho, Jae-Young
• Format: Article
• Language: English
• Subjects: Bark; Bioethanol; Crystallinity; Dilute acid; Dilution; Gamma irradiation; Hydrolysis; Lignocelluloses; Poplar; Poplar bark; Pretreatment; Sugars
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2012.01.001

Pretreatment of poplar bark with a combination of sulfuric acid (3%, w/w, H2SO4) and gamma irradiation (0–1000kGy) was performed in an attempt to enhance enzymatic hydrolysis for bioethanol production. The yields of reducing sugar were slightly increased with an increasing irradiation dose, ranging from 35.4% to 51.5%, with a 56.1% reducing sugar yield observed after dilute acid pretreatment. These results clearly showed that soluble sugars were released faster and to a greater extent in dilute acid-pretreated poplar bark than in gamma irradiation-pretreated bark. When combined pretreatment was carried out, a drastic increase in reducing sugar yield (83.1%) was found compared with individual pretreatment, indicating the possibility of increasing the convertibility of poplar bark following combined pretreatment. These findings are likely associated with cellulose crystallinity, lignin modification, and removal of hemicelluloses. ► Combined pretreatment increased the convertibility of poplar bark synergistically. ► The synergistic effect was due to enhancement of enzymatic hydrolysis. ► The combined pretreatment increased accessibility of enzyme to lignocellulose.