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The NSC-7 microbial community could decompose cellulose and lindan with high efficiency. In order to determine the bacterial composition of the community, 11 isolate strains were detected by plate isolation, while a community reset by the 11 isolate strains lost the 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. 195 clones and 25 strains were detected in clone library, and about 60% closest relative among them was known the detailed information which were belonged to Clostridium, Petrobacter, Bacteria, Paenibacillus, Proteobacterium. Furthermore, there were 40% closest relative belonged to uncultured bacterium clone.

The lignocelluloses of cassava residue are good biomass resources. They are mainly used to produce feeds and alcohol. It is a promising approach to utilize them to produce methane. But it is difficult to use cassava residue for producing methane because of its dispersive solid matter and much water. A cellulose degradation composite microbial system MC1 was applied to degrade cassava residue discarded from cassava starch manufactory, and the composition of the lignocelluloses and the soluble ingredients of cassava residue were analyzed. After 18 days' cultivation, the total weight of the cassava residue was reduced by 47.3%, the cellulose, hemi-cellulose and lignin of the cassava residue were reduced by 22.7%, 90.4% and 11.3%, respectively, and 85% of the whole weight relief was made by MC1 within 6 days. The soluble ingredients of the cassava residue were increased from the incipient 18% to 33% in the third day which was the peak value in the process. The total amount of the volatile products, analyzed by GC-MS, came to a maximum in the sixth day. Twelve kinds of volatile products in the fermentation broth were determined, in which ethanol, acetic acid, 1, 2-ethanediol, butanoic acid and glycerine were the major compounds, and they can be utilized by methanogenic organism directly or be changed into compounds that can be utilized by methanogens organism directly. Accordingly, it is very hopeful to use MC1 to degrade cassava residue as a method of prefermentation in methane fermentation.

The introduction of an exogenous cellulolytic bacterium into a microbial community that was degrading rice straw effectively was evaluated. A stable coexistence of the indigenous and exogenous cellulolytic bacteria was achieved by adjusting the cultivation conditions. The obtained community required several subcultures to reach the highest degradation efficiency.

The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model of pH values was as follows: irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0-9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity (under batch fermentation conditions) and longer interval (under semi-fermentation conditions) of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition of rice straw added one time every five days (under semi-fermentation conditions).

A cellulose-degrading defined mixed culture (designated SF356) consisting of five bacterial strains (Clostridium straminisolvens CSK1, Clostridium sp. strain FG4, Pseudoxanthomonas sp. strain M1-3, Brevibacillus sp. strain M1-5, and Bordetella sp. strain M1-6) exhibited both functional and structural stability; namely, no change in cellulose-degrading efficiency was observed, and all members stably coexisted through 20 subcultures. In order to investigate the mechanisms responsible for the observed stability, "knockout communities" in which one of the members was eliminated from SF356 were constructed. The dynamics of the community structure and the cellulose degradation profiles of these mixed cultures were determined in order to evaluate the roles played by each eliminated member in situ and its impact on the other members of the community. Integration of each result gave the following estimates of the bacterial relationships. Synergistic relationships between an anaerobic cellulolytic bacterium (C. straminisolvens CSK1) and two strains of aerobic bacteria (Pseudoxanthomonas sp. strain M1-3 and Brevibacillus sp. strain M1-5) were observed; the aerobes introduced anaerobic conditions, and C. straminisolvens CSK1 supplied metabolites (acetate and glucose). In addition, there were negative relationships, such as the inhibition of cellulose degradation by producing excess amounts of acetic acid by Clostridium sp. strain FG4, and growth suppression of Bordetella sp. strain M1-6 by Brevibacillus sp. strain M1-5. The balance of the various types of relationships (both positive and negative) is thus considered to be essential for the stable coexistence of the members of this mixed culture.

The capability of degrading rice straw of lignocellulolytic composite microbial system MC1 was investigated under different methods of preservation and temperatures treatments of 80 degrees C to 95 degrees C, and stability of composite microbial system MC1 was studied through the method of Denaturing Gradient Gel Electrophoresis (DGGE). The results indicate that the rice straw of 2% dry weight of medium can be degraded completely at 50 degrees C within 10 days under static culture. After 9 days inoculating MC1, the dry weight of rice straw, cellulose, hemicellulose and lignin content was degraded by 81% , 99%, 74% and 51%, respectively. Capability of cellulose degrading and stability of composite microbial system MC1 is sustained under 4 years of continuing subculture, 4 years of dry preservation at room temperature, 4 years of preservation at - 20 degrees C, 1 year of liquid preservation at room temperature and at 4 degrees C, and treatment of 90 degrees C for 30 min, respectively. Plate culture results show that composite microbial system MC1 are consisted of bacteria. The main DNA bands are not changed by the method of 16S rDNA PCR-DGGE after culture of six months so that microbial composition of MC1 is very stable.

A complex microbial system capable of degrading cellulose and lindane with high efficiency was isolated from four compost heaps. It was selected and domesticated through two methods and by combination of different microbial communities. The results show that the complex microbial system can decompose filter paper, absorbent cotton, rice straw powder and sawdust effectively, especially has high degrading activity for the materials with higher native cellulose such as filter paper and absorbent cotton. As for both of them, the CMC saccharification activity is more than 40U and the degradation efficiency is more than 95% on the 5th day of inoculation. The complex microbial system can also keep a higher degrading capability in a wider range of pH. Filter paper and lindane can be degraded effectively by the complex microbial system during pH 7.0 - 9.0, and the degradation rates are more than 90 % and 45% respectively. Under pH 6.0 - 9.0, there is a good consistency between the degradation of Lindane and the decomposition of filter paper.

A stable cellulose-degrading microflora enriched from composting materials has been analyzed in our laboratory. Cellulose-degrading efficiency of an anaerobic cellulolytic isolate, Clostridium straminisolvens CSK1, was remarkably lower than that of the original microflora. We successfully constructed bacterial communities with effective cellulose degradation by mixing C. straminisolvens CSK1 with aerobic non-cellulolytic bacteria isolated from the original microflora. Comparison of the cellulose degradation processes of the pure culture of C. straminisolvens CSK1 and the mixed-culture indicated that non-cellulolytic bacteria essentially contribute to cellulose degradation by supplying anaerobic environment, consuming metabolites, which otherwise deteriorate the cellulolytic activity, and by neutralizing pH.

A novel anaerobic, thermophilic and cellulolytic bacterium (strain CSK1(T)) was isolated from a cellulose-degrading bacterial community. On the basis of 16S rRNA gene sequence similarity, strain CSK1(T) was mapped to cluster III of the genus Clostridium. Strain CSK1(T) is closely related to Clostridium thermocellum (96.2 %) and Clostridium aldrichii (95.1 %). Strain CSK1(T) is a non-motile, spore-forming, straight or slightly curved rod. The optimum temperature and initial pH for its growth and cellulose degradation are 50-55 degrees C and pH 7.5. Strain CSK1(T) grew under a gas phase containing up to 4 % O(2). Phylogenetic and phenotypic analyses support the differentiation of strain CSK1(T) from its closest relatives. Strain CSK1(T) therefore represents a novel species, for which the name Clostridium straminisolvens sp. nov. is proposed, with CSK1(T) (=DSM 16021(T)=IAM 15070(T)) as the type strain.