Sugars Production for Green Chemistry from 2nd Generation Crop (Arundo donax L.) : a Full Field Approach

Arundo donax L. (giant cane) is a suitable feedstock for sugar production because of its high biomass yield and low agronomic input requirement. Eight A. donax clones were studied at full field scale for sugars production. 1-ethyl-3-methylimidazolium acetate - [C2C1im][OAc] - and enzymatic treatments were used to obtain the sugars. Highest glucose yields were obtained for pretreatment performed at 160 °C for 3 hours, with glucan conversion yields from 40.8 % to 76.2 % for most productive A. donax clones (AD10 and AD 20). Differences in cell wall structure measured by micropore surface area (pores of 0.3 - 1.5 nm) explained both ionic liquids and enzymatic performances of clones. Structural differences were due to the guaiacyl (G) and syringyl (S) units that determined different lignin cross-linking affecting cell wall microporosity and so enzyme accessibility. Total glucose and xylose yields (11 Mg Ha−1 and 4.84 Mg Ha−1, clone AD20), were impressive and about 3.5 to 4.5 times more than those obtainable from switchgrass and corn stover.