| Recently,with the continuous consumption of global resources,renewable resources have attracted great attention from all over the word.Cellulose is the most abundant renewable resources,and its transformation has become a heart issue.With the development of genomics and proteomics,there are more new ideas about the degradation of cellulose.In this study: Nowaday,we find the fungus that it can degrade cellulose and we get its genome.We find encoding gene EX22 of expansin-like protein that it can degrade cellulose by sequence alignment.So we want to prove the functon of the expansin-like protein from a strain Arthrobotrys sp.CX1 by experiment.We design specific primers to obtain the target fragment,then the recombinant was introduced into Pichia pastoris(X-33).The protein EX22 was purified via His-tag affinity chromatography to obtain relatively single protein.Finally,we study enzymatic properties and characterization methods.Experimental results demonstrate:(1)The protein EX22 is non-hydrolyzed protein,and it can degrade cellulose synergying with commercialized cellulase to improve the efficiency of cellulose degradation;(2)The crystallinity of cellulose descended 9.3% by XRD,that is pretreated by the protein EX22,the hydrogen bond content was decreased in the crystalline region and more hydroxyl groups were exposed by FT-IR;(3)Surface changes of different substrate observed by SEM,which can demonstrate that the protein EX22 can promote the entry of water molecules into cellulose molecules to break through the dense structure of the substrate by destorying hydrogen bond,and it causes an increase in looseness.Finally,we think that the protein(EX22)has a damaging effect on the hydrogen bonding of cellulose,and cellulose gets more easily degraded by breaking hydrogen bonds and entry of water molecules.But the mechanism of degrading cellulose is not clear,I believe that these will be revealed with the development of science and technology. |
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