Ultrastructural Analysis Of Crystalline Cellulose Degraded By Clostridium Thermocellum And Cellulosome

Lignocellulose accounted for 35-50% of the dry weight of green plant, it’s the most widely distributed and most abundant carbohydrate, thesynthesis and degradation of lignocellulose is the central point for circulation of carbon in nature. We can converse the lignocellulose to soluble sugar and biochemical production by enzymatic method, it’s critical for solution of energy crisis、environmental pollution. However, the lignocellulose is consist of cellulose.hemicellulose and pectin, which is difficult degraded, and the core cellulose is a supramolecular complex linked by β-1-4 glycosidic bond, such a supramolecular complex have multilevel crystal structure organized by hydrogen bond and Van der Waals force,the natural structure of cell wall forms a variety of protection mechanisms, and its resistance to microbial and enzymatic degradation fromation of "Biomass Recalcitrance", another reason of the low degradation efficiency is the special direction and contact face during of heterogeneous and layer-by-layerdegradation process by cellulase.Based on the troubles in the degradation process of cellulose. in this study, by the substrate characterization which different from traditional kinetics enzyme reaction, we determained the overall structural parameter of crystalline cellulose by overall measurement techniques, and we observe and analysis the crystalline celluloseby ultrasturctural means, in order to clarify the change of cellulose supramolecular structure in the degradation process by Clostridiem thermocellum and cellusome.We get the process as follow:Using Scanning Electron Microscope(SEM)andAtomic Force Microscopy(AFM)observed the crystalline cellulose degraded by Clostridiem thermocellum deeply, in the process,we found that Clostridiem thermocellum adhered to crystalline cellulose, generating the typicalmorphology characteristics:Gull, we analysis the width and deepth of the gull qualitatively and quantitatively, summarized the degradation mode for Clostridiem thermocellum.Purified thecomplex enzyme:cellusome. Established the purification system, optimized the enzyme activity of cellusome by selecting the carbon source and culture time for Clostridiem thermocellum, determained the optimum temperature and pH.Degraded the Whatman No.1 filter paper and crystalline cellulose PH105 by cellusome. Mersured the cellusome conversion ratio for crystalline cellulose by quantify the reducing sugar, capture the overall structural information by macroscopical means:FTIR and XRD test for the change of substrate element and crystallinity,Using the SEM and AFM combine slices to cahracterize the heterogeneity of cellulose supramolecular structure, we found that cellusome degraded the amorphous cellulose and small crystalline cellulose preferentially, the microfibril degraded by cellusome was rearranged but not cut absolutely.Compared and analysis the untreated Whatman No.1 filter paper, Whatman No.1 filter paper degraded by cellusome and Clostridiem thermocellum with 3D photograph, surface area and RMS roughness, Clostridiem thermocellumchange the morphology structure more apparently than cellusome. Clostridiem thermocellum. However, by analysis ofultrastructure, cellusome changed the overall morphology roughness and single microfibril height, but not obvious as Clostridiem thermocellum.