6782

6324

كارشناسي ارشد

مهندسي شيمي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي شيمي

1390

چهارده، 71ص.: مصور، جدول، نمودار

ص.ع.به فارسي و انگليسي

كيخسرو كريمي، طيبه بهزاد

محمد جعفر طاهرزاده

5/4/91

حميد زيلويي، اكرم زماني

1396/09/14

كتابنامه

مهندسي شيمي

مهندسي شيمي

ID6324

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Improved Saccharification and Fermentation of Rice Straw using Various Solvents for Pretreatment Step Nafiseh Poornejad n poornejad@ce iut ac ir February 20 2012 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiAssist Prof Keikhosro Karimi karimi@cc iut ac irAssist Prof Tayebeh Behzad tbehzad@cc iut ac irAbstractIncreasing demand for energy increases the importance of renewable resources to meet this great amount ofdemands Among different biofuels bioethanol has been taking the most attention Various resources could beused to biologically produce ethanol but lignocelluloses are of special interest because of having no conflictwith food resources Lignocellulosic materials considered as one of the best renewable resources for biofuelproduction are cheap and available in all over the world These materials are found in cell wall of plants Lignocelluloses are composed of three major polymers including cellulose hemicelluloses and lignin Packedand complex structure of these materials reduces their digestibility and therefore intensifies the significance of apretreatment step Rice straw among other lignocelluloses is the most available feedstock for bioethanolproduction Solvent based pretreatment by N methyl morpholine N oxide NMMO 1 buthyl 3 methylimidazolium acetate BMIM OAc and 1 ethyl 3 methylimidazolium acetate EMIM OAc was doneprior to enzymatic saccharification of rice straw N methyl morpholine N oxide is an industrial solvent nowused in fiber making process in Lyocell technology Ionic liquids are low melting point salts which are viscoseliquids in ambient temperature Treatment was performed in an oil bath at 120 C for 1 3 and 5 h with 5 solidloading Treated and untreated straws were subjected to enzymatic hydrolysis at 45 C for 72 h by 20 FPU g ofsubstrate cellulase and 30 IU g of substrate glucosidase Hydrolysis was performed in a shaker incubator withthe speed of 100 rpm Glucose released was meatured using glucose HK assay kit Simultaneoussaccharification and fermentation was carried out at 38 C for 48 h using Saccharomyces cerevisiae asfermenting organism in an incubator with the speed of 80 rpm Produced ethanol was determined by HPLC Hydrolysis results indicated relatively complete conversion of glucan to glucose for all treated straws Glucoseyields were more than 96 for all treated samples while this value was only 27 7 for untreated straw Ethanolyield compared to maximum theoretical yield was improved from 35 4 for untreated straw to 93 3 79 7 and 79 7 after pretreatment with NMMO EMIM OAc and BMIM OAc respectively FTIR analysisindicates reduction in crystalline matrix of straw Crystallinity Index of straw reduced from 0 46 for untreatedstraw to less than 0 37 for all pretreated straws In addition confirmed by SEM images of various samples structural destruction is one of the main reasons for observed improvements NMMO was the best solventamong applied solvents in term of ethanol production per initial straw 20 8 g bioethanol could be produced per100 g of initial straw using a pretreatment step by NMMO at 120 C for 5 h while this value was only 8 3 g foruntreated straw It means potential annual production of 250 billion liter ethanol of 955 million ton producedrice straw in all over the world Key Words Rice straw NMMO BMIM OAc EMIM OAc lignocelluloses ionic liquid

كيخسرو كريمي، طيبه بهزاد

محمد جعفر طاهرزاده

حميد زيلويي، اكرم زماني