title: Using a combined hydrolysis factor to optimize high titer ethanol production from sulfite-pretreated poplar without detoxification.
abstract: Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) was applied to poplar NE222 chips in a range of chemical loadings, temperatures, and times. The combined hydrolysis factor (CHF) as a pretreatment severity accurately predicted xylan dissolution by SPORL. Good correlations between CHF and pretreated solids enzymatic digestibility, sugar yield, and the formations of furfural and acetic acid were obtained. Therefore, CHF was used to balance sugar yield with the formation of fermentation inhibitors for high titer ethanol production without detoxification. The results indicated that optimal sugar yield can be achieved at CHF=3.1, however, fermentation using un-detoxified whole slurries of NE222 pretreated at different severities by SPORL indicated CHF≈2 produced best results. An ethanol titer of 41 g/L was achieved at total solids of approximately 20 wt% without detoxification with a low cellulase loading of 15 FPU/g glucan (27 mL/kg untreated wood).
authors: School of Life Sci. Technol., Beijing Univ. Chem. Technol., Beijing, China; USDA Forest Service, Forest Products Laboratory, Madison, WI, USA.
authors: Jingzhi
authors: J
authors: Zhang
authors: USDA Forest Service, Forest Products Laboratory, Madison, WI, USA; Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing, China.
authors: Feng
authors: F
authors: Gu
authors: USDA Forest Service, Forest Products Laboratory, Madison, WI, USA. Electronic address: jzhu@fs.fed.us.
authors: J Y
authors: JY
authors: Zhu
authors: USDA Forest Service, Northern Research Station, Rhinelander, WI, USA.
authors: Ronald S
authors: RS
authors: Zalesny
mesh_terms: D056804:Biofuels; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000302:isolation & purification*; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry*; D032107:Populus / Q000737:chemistry*; D013447:Sulfites / Q000737:chemistry
chemical_list: D056804:Biofuels; D013447:Sulfites; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin
keywords: Cellulosic biofuel; Fermentation inhibition; High solids processing; Poplar woods; Pretreatment optimization