| Cellulose account for more than 50 percent of the primary product of photosynthesis in terrestrial environments,and the most abundant renewable bioresource produced in the biosphere(200 billion dry tons/year),lignocellulose in wood,straw,agricultural waste, livestock dejecta and so on.The cellulose molecule is very stable,which restrict its widely used to produce sustainable biobased products and bioenergy to replace depleting fossil fuels.The synergic mechanism and microbial component diversity of the microbial community NSC-7 with efficient cellulose and lindan degradating ability was determined.The results showed that NSC-7 could degrade 73.6%of rice staw in weight,including 82.1%of cellulose, 58.2%of hemicellulase,and 5.4%of lignin within fourteen days.In addition,ethanol,propiolic acid,acetic acid,ethanedioic acid diethyl ester,propionic acid 2-methyl,urea,pentanol, butanoic acid,ethanol,2,2-oxybis and glycerin the ten kinds of material were detected in volatile products by gas chromatography mass spectrometry(GC-MS).NSC-7 could produce cellulase and hemicellulase simultaneity.And the maximum of endoglucanases,exoglucanases,β-glucosidases and the total cellulase activity were 4.48 U/mL,15.83 U/mL,25.78 U/mL and 7.5 U/mL,respectively,on the day 8,and the maximum of hemicellulase activity were 280.6 U/mL on the day 5.For determine the bacterial compose of the community,11 isolate strains were detected by plate isolation under aerobic condition,while the community reset by the 11 isolate strains without capacity of degrading cellulose.The capacity of degrading of the filter paper in double deck plate and monolayer plate were determined,only the filter paper in double deck plate were degraded,that means the main or key microbe are anaerobic.The Denaturing Gradient Gel Electrophoresis(DGGE) and construction of 16S rDNA clone library were used to identify the composition diversity of NSC-7 community,with 25 strains detected,in that about 60% closest relative among them was know the detailed information and they were belonged to Clostridium,Petrobacter,Bacteria,Paenibacillus,proteobacterium respectively.Furthermore, there were 40%closest relative belonged to uncultured bacterium clone.Due to the isolate strains without capacity of degrading cellulose,a conclusion could be made that the key microbe may be in the uncultured bacterium of Clostridium sp.According to the character of Clostridium sp.with the capability of adhibit in the cellulose power in degradation process,therefore,washing by the PBS buffer and centrifuging the deposition were used to isolated the Clostridium sp.However,we obtained the microbial community "key microbial community " with three strains(Uncultured bacterium clone,Clostridium sp. PML14 16S,Clostridium straminisolvens)which could not be isolate until now.The "key microbial community" was assembled with three isolates which without the capability of degradation cellulose(Pseudoxanthomonas taiwanensis,Bacillus sp.Petrobacter sp.).The results showed that the two isolates(A-Pseudoxanthomonas taiwanensis and 6-Petrobacter sp.) could promot the degradation capability of "key microbial".More research found that the two isolates with the capability of high degradated and utilized cellobiose,a conclusion was deduce that utilized cellobiose maight be the main reason for isolate improve the cellulose degradation.The microbial community NSC-7 was treated under 90℃,100℃,105℃and 110℃temperature about 30 min.After treated,each of them still with the cellulose degradating ability,however,the kinds and quantity of microbial and the kinds of volatile products became less than before,and the ability of degration cellulose became less efficient than before.While with the subculture times increased,the capability of the degradation resume.
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