Study On Enhancement Of High Solid Saccharification Fermentation Of Caragana Korshinskii Kom By Steam Explosion

At present,the research on cellulosic ethanol mainly focuses on herbaceous plants,while the research on woody plants is less.In this paper,Caragana korshinskii Kom(CKK)(woody plant)was used as raw material,and wheat straw(WS)(herbaceous plant)and microcrystalline cellulose(MCC)(pure cellulose)were used as control to strengthen the production process of cellulosic ethanol.Steam explosion wheat straw and steam explosion coupled alkali pretreatment of Caragana korshinskii Kom,the enzymatic conversion of glucan reached 40.48%and 53.36%,Steam explosion wheat straw and steam explosion coupled alkali pretreatment of wheat straw,the conversion of glucan reached 56.27%and 70.27%respectively..10.43 g,10.69 g,10.28 g and 11.15 g of glucose were obtained from 100 g wheat straw and Caragana korshinskii after steam explosion pretreatment(SEP)and alkali treatment(SAP)respectively.It can be found that the combined pretreatment is not obvious to promote the yield of glucose,so steam explosion pretreatment is selected as the treatment method of Caragana korshinskii in this study.The physical and chemical structures of steam explosion wheat straw and Caragana korshinskii were analyzed by means of scanning electron microscopy(SEM),Fourier transform infrared(FTIR)and X-ray diffraction(XRD).The results of SEM showed that steam explosion pretreatment significantly damaged the surface integrity of Caragana korshinskii and wheat straw,and exposed the internal structure of cells.FTIR analysis showed that the characteristic peaks of cellulose(especially cellulose in amorphous zone)and lignin increased significantly after steam explosion,while the characteristic peaks of hemicellulose basically disappeared.This indicated that the content of cellulose and lignin increased after steam explosion pretreatment,and the proportion of cellulose in amorphous zone increased significantly.XRD analysis showed that the natural structure of cellulose did not change significantly.In this study,MCC,SEPW and SEPK were used as substrates to enhance enzymatic hydrolysis with low cellulase content and high solid batch feeds.Through orthogonal experiments,the enzymatic hydrolysis efficiency of the three substrates reached reached the theoretical maximum(90%,90%and 90%)of 51.82%,66.90%and 59.82%.The structure analysis after enzymatic hydrolysis showed that the cellulose exposed to SEPK and SEPW disappeared,the content of amorphous cellulose decreased significantly,and the crystallinity increased.The yield of ethanol was 57.99%,64.40%and 63.41%of the theoretical yield(71.69 g/L,65.09 g/L and 66.71 g/L),respectively,using MCC,SEPW and SEK as substrates.