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This study investigated the requirement of cellobiohydrolases (CBH) for saccharification of microcrystalline cellulose and sugarcane bagasse pretreated either by ball milling (BM) or by ionic liquid (IL) [Emim][Ac]. Hydrolysis was done using CBH-free blends of Pyrococcus horikoshii endoglucanase (EG) plus Pyrococcus furiosus β-glucosidase (EGPh/BGPf) or Optimash™ BG while Acremonium Cellulase was used as control. IL-pretreated substrates were hydrolyzed more effectively by CBH-free enzymes than were the BM-pretreated substrates. IL-treatment decreased the crystallinity and increased the specific surface area (SSA), whereas BM-treatment decreased the crystallinity without increasing the SSA. The hydrolysis of IL-treated cellulose by EGPh/BGPf showed a saccharification rate of 3.92 g/Lh and a glucose yield of 81% within 9h. These results indicate the efficiency of CBH-free enzymes for the hydrolysis of IL-treated substrates., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Ozonolysis was studied separately and in combination with wet disk milling (WDM) for the pretreatment of sugarcane bagasse and straw, with the aim of improving their enzymatic saccharification. The glucose yields for ozonolysis followed by WDM were 89.7% for bagasse and 63.1% for straw, whereas the use of WDM followed by ozonolysis resulted in glucose yields of 81.1% for bagasse and 92.4% for straw, with shorter WDM time. This last procedure allowed a substantial decrease in energy consumption in comparison to the use of WDM alone or of ozonolysis followed by WDM. Higher overall saccharification yields with shorter milling times were observed when ozonolysis was carried out before WDM. This effect might be related to the higher specific surface area. Additionally, a finer morphology was observed by the association of the two treatments in comparison to the sole use of ozonolysis or WDM., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In this study, sugarcane bagasse was pretreated by six ionic liquids (ILs) using a bagasse/IL ratio of 1:20 (wt%). The solubilization of bagasse in the ILs was followed by water precipitation. On using 1-ethyl-3-methylimidazolium acetate [Emim] [Ac] at 120 °C for 120 min, 20.7% of the bagasse components remained dissolved and enzymatic saccharification experiments resulted on 80% glucose yield within 6h, which evolved to over 90% within 24 h. Moreover, FE-SEM analysis of the precipitated material indicated a drastic lignin extraction and the exposure of nanoscopic cellulose microfibrils with widths of less than 100 nm. The specific surface area (SSA) of the pretreated bagasse (131.84 m2/g) was found to be 100 times that of untreated bagasse. The ability of [Emim] [Ac] to simultaneously increase the SSA and to decrease the biomass crystallinity is responsible for the improved bagasse enzymatic saccharification rates and yields obtained in this work., (Copyright © 2011 Elsevier Ltd. All rights reserved.)