| Fuel ethanol production from lignocellulosic materials is a potential alternative to solve the energy and environmental problems and maintain social sustainable development. This thesis evaluated the pretreatment and enzymatic hydrolysis of lignocellulosic materials via microwave technology. The pretreatment, enzymatic hydrolysis and ethanol fermentation of rice straw, a model lignocellulosic material, were systematically investigated. To our knowledge, application of microwave technology in pretreatment and enzymatic hydrolysis of lignocellulosic materials hasn't been reported before.Firstly, different microwave-assisted pretreatments of rice straw were evaluated and compared with conventional alkali pretreatment. The microwave/alkali pretreatment could increase the initial enzymatic hydrolysis rate of pretreated rice straw and the reducing sugar yield from the hydrolysis remained unchanged. When the enzymatic hydrolysis was run for 7 d in a water-bath thermostat at substrate concentration (10 g.l-1) and the optimization objective was the highest reducing sugar yield from the hydrolysis, the optimal microwave/alkali pretreatment condition was that the rice straw in 1% NaOH solution was microwave-irradiated for 6 min at 700 W; the optimal hydrolysis conditions were temperature (45℃), pH (4.8) and enzyme loading (20 mg.g-1 substrate). The enzymatic hydrolysis of microwave/alkali pretreated rice straw was also investigated when the enzyme solution was microwave-irradiated at 300 W or the reaction mixture was intermittently microwave-irradiated at 300 W during the hydrolysis. When the enzyme solution was microwave-irradiated, the initial hydrolysis rate was slightly increased but the reducing sugar yield was decreased remarkably. When the reaction mixture was intermittently microwave-irradiated during the hydrolysis, the initial hydrolysis rate was greatly increased while the reducing sugar yield was slightly decreased. The reason is that microwave irradiation affected the cellulase activity (its filter paper activity and CMC saccharification activity were improved but its cellobiose activity was decreased).Comparison of the main chemical components and enzymatic hydrolysis was made between microwave/alkali pretreated rice straw and conventional alkali pretreated rice straw. The microwave/alkali pretreated rice straw had higher cellulose content and fast hydrolysis rate, and its hydrolysate had higher glucose concentration. Then microwave/alkali pretreatment, microwave/acid/alkali pretreatment and microwave/acid/alkali/ H2O2 pretreatment were compared. Besides the xylose could be recovered during microwave/acid/alkali/ H2O2 pretreatment, the pretreated rice straw had highest cellulose content and fast hydrolysis rate, and its hydrolysate had highest glucose concentration. The microwave/acid/alkali/ H2O2 pretreatment was the best rice straw pretreatment method among these pretreatment methods.The enzymatic hydrolysis kinetics studies were carried out for conventional alkali pretreated rice straw, microwave/alkali pretreated rice straw and microwave/acid/alkali/ H2O2 pretreated rice straw. Their hydrolysis were all competitively inhibited by their product (reducing sugar) and could be described as follows:dtFor conventional alkali pretreated rice straw, Rpmax=1.36g.l'1.h"1, Km=17.9g.r1, and KG=29.9g.l"1.For microwave/alkali pretreated rice straw, Rpmax=2.06g.r1.h"1, Km=18.3g.l"1, and KG=29.6g.l"1.For microwave/acid/alkali/ H2O2 rice straw, Rpmax=2.80g.r1.h"1, Km=17.4g.l"1, and KG=43.1g.l"1.Finally, comparison was made among conventional alkali pretreated rice straw, microwave/alkali pretreated rice straw and microwave/acid/alkali/ H2O2 pretreated rice straw based on their hydrolysate ethanol fermentation and batch simultaneous saccharification and ethanol fermentation. The microwave/acid/alkali/H2O2 pretreated rice straw had the highest final ethanol concentration and yield. It was further proved that the microwave/acid/alkali/H2O2 pretreatment was the best ricestraw pretreatment method among these pretreatment methods. For the microwave/acid/alkali/H2O2 pretreated rice straw, comparison was also made between its fed-batch and batch simultaneous saccharification and ethanol fermentation. The fed-batch simultaneous saccharification and ethanol fermentation could achieve higher final ethanol concentration by successfully solving the mixing problem. The optimal conditions for the fed-batch simultaneous saccharification and ethanol fermentation were temperature (40"C), initial pH (5.3), initial feeding time (36 h), feeding amount for each time (3 g, 3 g, 2 g, 2 g), nutritional components' concentration (1.8 times that of the standard basal media) and enzyme loading (12.5 mg.g^substrate). Under the optimal conditions, the final ethanol concentration and yield were 57.3 g.l"1 and 60.3 % respectively.
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