Effect Of Ultrasound-assisted Phanerochaete Chrysosporium Pretreatment On Enzymatic Saccharification Of Distillers Grains

Distillers grains(DG), a by-product of brewing industry in China, but the vast majority of DG are disposed directly, it not only produced solid waste polluting, but also caused great waste of biomass resource. This paper was lignocellulosic biomass to produce fuel ethanol and other biofuels raw material of DG, study the effect of physical and biological pretreatment method of DG, the main research contents are as follows:1. Study on the effect of ultrasound pretreatment of DG.The yield reducing sugar and xylose as evaluation index to identify the conditions of pretrement, effects of the enzymme(cellulase and xylanase)dosage, enzymolysis time and solid-liquid ratio were investigated; and the influences of ultrasound power, time of ultrasound treatment, temperature,solide liquid rate(SLR) were studied. The processing conditions were optimized by response surface methodology(RSM).The results indicate that the optimum conditions was ultrasound power420 W,temperature 40℃, time 39 min, and solide liquid ratio 1:22(g/m L).Under optimal conditions the holocellulose retention rate,and degradation rate of the lignin was 69.02% and 20.47%, reducing sugar and xylose yield were 70.73% and 35.77% respectively. Quadratic regression model shows that under the holocellulose retention rate, lignin degradation rate, reducing sugar and xylose yield model were significantly,can be used for the optimization of DG ultrasonic pretreatment.2. Studied the Phanerochaete chrysosporium pretreatment processing of DG The paper used Phanerochaete chrysosporium pretreatment DG, study the effect of solid state fermentation of Phanerochaete chrysosporium of enzyme hydrolysis and the Phanerochaete chrysosporium growth curve,analysis of the component changes during the process of pretreatment and enzymatic hydrolysis characteristics. Results showed that Phanerochaete chrysosporium at training time for 120 h its activity is highest, was the best age of inoculant. As the extension of Phanerochaete chrysosporium pretreatment time, reducing sugar and xylose yield were downward trend after rising first, and in solid state fermentation time for 8 d white-rot fungus, enzymolysis liquid of reducing sugar and xylose yield reached a maximum of 60.55%and 22.12%. Compared with the untreated enzymatic hydrolysis yield increased by 49.22% and 25.0%, respectively. The holocellulose retention rate and lignin degradation rate were 73.13% and15.58%, respectively.3. Effect of ultrasound-assisted Phanerochaete chrysosporium pretreatment on enzymatic saccharification of distillers grains :(1) The effect of different pretreatment methods of DG showed that :after optimal ultrasonic conditions pretreatment, inoculation 30%Phanerochaete chrysosporium, cultivate 8d, residues was enzymetic hydrolysis by cellulase and xylanase, the reducing sugar and xylose yield were 74.65% and 51.69%, respectively. Composition analysis shows that ultrasonic pretreatment the holocellulose retention rate and lignin degradation rate were 69.02% and 20.47% respectively, the single Phanerochaete chrysosporium pretreatment residue the holocellulose retention rate and lignin degradation rate were 73.13% and 15.58%,respectively, and ultrasound-assisted Phanerochaete chrysosporium pretreatment residue the holocellulose retention rate and degradation rate of the lignin were 88.70% and 40.03%.(2) Analysis of DG residue’s structure before and after pretreatment,The SEM, X-ray diffraction and FTIR showed that pretreatment results in the structure was destructioned, the cellulose crystallinity increase and part of lignin were degradated of DG.Results show that ultrasonic pretreatment and enzymolysis of DG, the reducing sugar and xylose yield were 70.73% and 35.77%; After Phanerochaete chrysosporium pretreatment of enzymatic hydrolysis,reducing sugar and xylose yield were 60.55% and 22.12%, respectively;ultrasound-assisted Phanerochaete chrysosporium pretreatment can effectively improve the yield of enzymatic, the yield of reducing sugar and xylosewere 74.65% and 51.69%.