Optimization by response surface methodology of processing conditions for the ionic liquid pretreatment of energy cane bagasse

Abstract

BACKGROUND Ionic liquids are generally considered to be green solvents, and can be potential substitutes for traditional flammable and volatile solvents due to such suitable properties as low volatility, high thermal stability, non‐flammability, and good recyclability. This study aimed to optimize 1‐ethyl‐3‐methylimidazolium acetate ([EMIM][OAc]) pretreatment processing conditions by evaluating the effect of three pretreatment processing parameters (temperature, residence time and solids loading) on the enzymatic hydrolysis of [EMIM][OAc]‐treated energy cane bagasse via response surface methodology (RSM). RESULTS The model fitted by RSM indicated that a higher glucose yield of [EMIM][OAc]‐treated biomass could be obtained at higher pretreatment temperatures with shorter residence times within the design space. The optimal processing conditions were pretreatment of energy cane bagasse at 131.9°C for 28.1 min at 8.4% solids loading, resulting in a final glucose yield of 35.96 g glucose per 100 g of native biomass compared with the predicted value of 35.89. CONCLUSION The results suggest that this model can predict accurately the glucose yield within the specified design space. The model can also provide valuable insight to further industry application. © 2013 Society of Chemical Industry

Characterization of white poplar and eucalyptus after ionic liquid pretreatment as a function of biomass loading using X-ray diffraction and small angle neutron scattering

“…The general trend is that hemicellulose loss decreased with increasing biomass loading.It is interesting to notice that the mass loss of lignin, shown in Figure 1d, remains roughly the same as the biomass loading varies for both the pine and white poplar. Several prior studies have showed that lignin removal efficiency was observed to decrease as the biomass loading was increased (Cruz et al, 2013;Qiu et al, 2014;Wu et al, 2011). In this work, the amount of anti-solvent water added to the IL/biomass slurry at the end of pretreatment was not fixed to that of the IL used, i.e., it increased from ~6 to 40 times of IL with increasing of biomass loading.…”

“…Higher biomass loading is desirable during IL pretreatment since less amount og ILs is used. Yet, the number of studies which explored higher biomass loading is rather limited (Cruz et al, 2013;da Silva et al, 2013;Qiu et al, 2014;Wu et al, 2011). In 2011, Wu et al conducted pretreatments at different biomass loadings of corn stover and found that the effectiveness of lowering biomass crystallinity index (CrI) decreased with increasing biomass loadings from 4.8 to 33 wt.% during pretreatments (Wu et al, 2011).…”

Enzymaticin situsaccharification of rice straw in aqueous-ionic liquid media using encapsulatedTrichoderma aureoviridecellulase

“…Recently, ionic liquids (ILs) have been increasingly recognized as novel solvents for dissolution and pretreatment of lignocellulosic biomass . Several studies have demonstrated that cellulose regenerated from IL was essentially amorphous and more prone to hydrolysis by cellulase .…”

Liberation of fermentable sugars from soybean hull biomass using ionic liquid 1‐butyl‐3‐methylimidazolium acetate and their bioconversion to ethanol

“…The authors observed the formation of coagulates under the combination of long time‐high temperatures. Qiu et al observed the same coagulation process when pretreated cane bagasse with [emim][Ac] at high temperatures (>120°C) and long residence time (>40 min). The increased amount of hydrogen bonds between cellulose and IL is the probable cause of the coagulation .…”

“…Qiu et al observed the same coagulation process when pretreated cane bagasse with [emim][Ac] at high temperatures (>120°C) and long residence time (>40 min). The increased amount of hydrogen bonds between cellulose and IL is the probable cause of the coagulation . These coagulates make more difficult the regeneration of the cellulose and may contain residual IL, even after washing the pretreated biomass.…”