Studies On Effect Of γ Irradiation Degradation Of Rice Srtaw And Enzymatic Hydrolytic Optimal Technology

To actively develop renewable energy is an alternative way to cope with the energy crisis and environmental pollution.The biomass energy is one of the most abundant renewable energy source. The major raw material of biomass energy is natural lignocellulose. How to disrupt lignocellulose structure and to improve enzymatic hydrolysis is the bottleneck of biofuel product.At present, there are many methods have been widely used to pretreat natural lignocellulose materials, such as physical method, chemical method, biological method, physical & chemical method, combining method and so on. However,there are some drawbacks,such as low efficiency, high cost,pollut environment and so on.Therefore it is necessary to develop new pretreative technology.The analysis method was establish to determine the content of the cellulose, hemicellulose and lignin of 60Co y-rays irradiated rice straw. Soluble sugars were measured qualitatively and quantitatively by Ion chromatography.The apparent structures of irradiated rice straw were scanned by electronmicroscope.The structures of irradiated monosaccharide,oligosaccharide,pure cellulose and lignin were analysed by Infrared transform spectrometer.Treated by both irradiation and enzyme,rice straw's saccharification effect was researched.Parameters of irradiation and enzymolysis of rice straw were studied and optimization technology were established.Water-soluble sugars and enzymolysis effect of rice straw were researched, which was pretreated by irradiation and steam explosion respectively.These researches provide theoretical and technical supports for irradiation pretreatment.The experimentsal results as follows:1 Analytical methods of rice straw's compositionThe method to determine cellulose,hemicellulose and lignin content was established.NDF and ANF were measured at first,then using 70% acetic acid to dissolve lignin. According to sent heavy, the contents of cellulose, hemicellulose and lignin in rice straw were 23.98%,35.88%,11.19% respectively.Water-soluble sugars in rice straw were determined by IC. There were a little lactulose, glucose and cellobiose in rice straw without pretreatment.2 The variation of cellulose, hemicellulose and lignin content in irradiated rice strawThe variation of cellulose, hemicellulose and lignin content in irradiated rice straw was acquired definitely.From OkGy to 2000kGy, with irradiation dose rising, the content of cellulose was reduced from 30.73% to 21.93%; the content of hemicell uloserise was 10.15% to 5.28%; the contents of lignin was reduced from 8.88% to 7.25%.3 Analysis the apparent structures of irradiated rice strawThe apparent structures of irradiated rice straw was analysed by SEM.The apparent structures of irradiated rice straw had no change at low dose,but above 800kGy doses,it becomed porosity and loose. Internal surface becomed more porosity at 2000 kGy.4 Analysis the structural feature of irradiated monosaccharide, oligosaccharide, pure cellulose and ligninThe structural feature of irradiated monosaccharide, oligosaccharide, pure cellulose and lignin was analysed by Infrared spectrometer. The C-O-C structure in monosaccharide,oligosaccharide and pure cellulose was oxidatived to C=O structure. The cyclobenzene of lignin was influenced by irradiation treatment.5 Optimization of enzymolysis of rice strawOptimal enzymatic hydrolysis conditions of rice straw were 45℃enzymatic hydrolysis temperature,180U/g enzyme dosage,60h enzymatic hydrolysis time and 60:1 liquid-solid ratio. It was optimized by Lg(34) orthogonal experiment. The influence of enzymatic hydrolysis temperature, enzyme dosage, enzymatic hydrolysis time was significant. The influence of liquid-solid ratio was not significant.6 Optimization of enzymolysis of irradiated rice strawOptimal enzymatic conditions of irradiated rice straw were 150 U/g enzyme dosage, 800kGy irradiational dose,48h enzymatic hydrolysis time and 50:1 liquid-solid ratio. It was optimized by L9(3) orthogonal experiment. The influence of enzyme dosage and irradiational dose was significant. The influence of enzymatic hydrolysis time and liquid-solid ratio was not significant.7 Contrast y-irradiation and steam explosion pretreatment to rice strawContrast y-irradiation and steam explosion pretreatment to rice straw.Compared to irradiative pretreatment, the content of glucose and xylose in steam explosive rice straw was smaller.But the contents of stachyose, gossypose and glucuronic acid were larger. At the same enzymatic conditions, the contents of glucose and xylose were 90.355 mg/g and 85.448 mg/g respectively,which from 800kGy dose and 2.0 Mpa 2.0 min steam explosion pretreatment rice straw respectively.