Study Of One-pot Process Of Corn Straw Cellulose Pretreated By Ils And Converted To Fuel Ethanol

Lignocellulose converted to bioethanol is currently a hot subject in bioenergyconversion research. In this thesis, the effect on activity, stability of cellulase by ILscan dissolve cellulose were studied. The one-pot and two-step process of corn strawcellulose pretreated by ILs and converted to bioethanol were also studied farther.The activity and stability of cellulase in presence of [BMIM]Cl, [AMIM]Cl,[MMIM][Me2PO4], [EMIM][Et2PO4] or [BMIM][Bu2PO4] were investigated in thisthesis. The ability of these ILs to inhibit the activity of cellulase were in the order of[BMIM]Cl> [AMIM]Cl> [BMIM][Bu2PO4]> [EMIM][Et2PO4]> [MMIM][Me2PO4];the ability to keep stability of cellulase were contrary in the order of [MMIM][Me2PO4]> [EMIM][Et2PO4]> [BMIM][Bu2PO4]> [AMIM]Cl> [BMIM]Cl。.[BqMIM]Cl and [AMIM]Cl that are two of the best ionic liquids can dissolvecellulose effected on the inhibition of cellulase activity significantly higher thanphosphonate kind of ionic liquids, the stability of the cellulase are even worse, theyare not suitable for one-pot process. For phosphonate kind of ILs,the largest residualactivity of the cellulase in different concentrations buffer-IL [BMIM][Bu2PO4] threedays later were 33.7% of residual activity in citric buffer, the comparative activitywas much smaller, indicating a strong inhibitory effect on cellulase, not suitable forone-pot process studies; The relative residual activity of the cellulase three days laterwere all less than 30% in high concentration(>30%)buffer-ILs([MMIM][Me2PO4]or[EMIM][Et2PO4]), they were also not suitable for one-pot process; The initialactivities of the cellulase were 71.9% and 63.2% of the initial activity in citric bufferand the residual activities three days later were 82.1% and 75.3% of each initialactivity in 10% buffer-ILs([MMIM][Me2PO4] or [EMIM][Et2PO4]). As a result, theeffect of ILs on cellulase was not obviously and the one-pot process could carry outunder this condition. So in the one-pot process of the experiment, selecting a lowphosphonate kind of ILs content as the studyobject.The one-pot and two-step processes of corn straw cellulose pretreatment withcellulase combined with microwave 800w were studied. In one-pot process thehydrolysis yield of corn straw cellulose pretreated by [MMIM][Me2PO4] with 5%solid content was 2.42 times of the untreated after hydrolysis for 4ds, while 1.95 timesby [EMIM][Et2PO4] with solid content 2.5%, however, the hydrolysis yield pretreatedby [BMIM][Bu2PO4] was lower than the untreated corn straw cellulose. It indicated that [BMIM][Bu2PO4] was not fit for the study of one-pot process. In two-stepprocess, the highest hydrolysis yield of corn straw cellulose pretreated by [MMIM][Me2PO4], [EMIM][Et2PO4] or [BMIM][Bu2PO4] were 3.08, 2.25 and 1.18 times ofthe untreated. The results of research on pretreated time at solid content 5% in one potprocess showed that the optimal time was 92s pretreated by [MMIM][Me2PO4], while104 s by [EMIM][Et2PO4]. To make the reaction economical, power consumption aslow as possible, enzyme hydrolysis yield also as high as possible, particle size of cornstraw was selected <1mm more reasonable.There glucose fermentation solution containing [MMIM][Me2PO4] and [EMIM][Et2PO4], the ratio of ionic liquid with minimal impact on the fermentation was 10%for [MMIM][Me2PO4], while 15% for [EMIM][Et2PO4], and the ratio of [EMIM][Et2PO4] was 15%, ionic liquid had almost no effect on yeast fermentation. Thehydrolyzate of corn straw that pretreated by [MMIM][Me2PO4] with 5% solid contentand enzymatic hydrolysis could be directly used for fermentation into ethanol, theyield of ethanol was highest at this time. Corn straw cellulose pretreated by ILs andconverted to bioethanol were also studied farther. So [MMIM][Me2PO4] was the idealionic liquid that pretreated and converted corn straw cellulose into fuel ethanol inone-pot process. When the ratio of ionic liquid increased, [EMIM][Et2PO4] had lesseffect on the fermentation process, therefore, [EMIM][Et2PO4] also had researchpotential in one-pot process. Integrated throughout the experimental study, [MMIM][Me2PO4] was the most suitable ionic liquid for studying the one-pot process.