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 communit...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 ofpH 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 office straw added one time every five days （under semi-fermentation conditions）.展开更多
To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and ad...To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution（50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula） kg–1 straw dry matter, or spraying a large amount of culture broth（1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth） on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter（DM） and crude protein（CP） concentrations, lower neutral detergent fiber（NDF）, acid detergent fiber（ADF） and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM（IVDMD）. The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.展开更多
This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry comp...This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry compost system. Denaturing gradient gel electrophoresis （DGGE）, gene clone library, temperature, C/N ratio, and the germination index were employed for the investigation, cow manure compost was used as the control. Results showed that the basic strip and dominant strips of the DGGE bands for biogas slurry compost were similar to those of cow manure compost, but the brightness of the respective strips for each system were different. Shannon-Weaver indices of the two compost systems differed, possessing only 22% similarity in the primary and maturity stages of the compost process. Using bacterial 16S rRNA gene clone library analysis, 88 bacterial clones were detected. Further, 18 and 13 operational taxonomic units （OTUs） were present in biogas slurry and cow manure compost, respectively. The 18 OTUs of the biogas slurry compost belonged to nine bacterial genera, of which the dominant strains were Bacillus sp. and Carnobacterium sp.; the 13 OTUs of the cow manure compost belonged to eight bacterial genera, of which the dominant strains were Psychrobacter sp., Pseudomonas sp., and Clostridium sp. Results demonstrated that the duration of the thermophilic phase （more than 50°C） for biogas slurry compost was 8 d less than the according duration for cow manure compost, and the maturation times for biogas slurry and cow manure compost were 45 and 60 d, respectively. It is an effective biogas slurry assimilate technology by application of biogas slurry as nitrogen additives in the manufacture of organic fertilizer.展开更多
In order to study degradation capability and optimal condition of produced endoglucanase （CMCcase）, the microbial community with efficient cellulose degrading ability in 28℃ was studied. Microbial community came fr...In order to study degradation capability and optimal condition of produced endoglucanase （CMCcase）, the microbial community with efficient cellulose degrading ability in 28℃ was studied. Microbial community came from rotted rice straw which was enriched and domesticated by improved Mandels medium. The standard cellulase activity assays were used to determine cellulase activity, degradation products were analyzed by gas chromatography mass spectrometry （GC/MS）, and denaturing gradient gel electrophoresis （DGGE） was used to identify the composition dynamic of the community. The results showed that the microbial community could degrade 39.6% of rice straw gross weight within 6 d. When culture medium volume was 1/5 and pH = 6 on day 5, the CMCcase activity reached the highest of 14 IU mL-L During the fermentation, more than ten products were detected using GCMS. The microbial changed lots in different fermentation periods which detected by DGGE. Phylogenetic tree derived from 16S rDNA sequence found that the community composed of bacteria, and the closest relative were belong to Clostridium sp., Brevibacillus sp. and Bacterium sp. This microbial community could accelerate rice straw rotting and decomposed products could promote organic matter increase of soil展开更多
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA245031) the National Key Project of the"10thFive-Year"Program of China (No. 2002BA516A03)
文摘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 ofpH 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 office straw added one time every five days （under semi-fermentation conditions）.
基金supported by the National Key Technology Research and Development Program of China during the 12th Five-Year Plan period (2012BAD14B01)the Special Fund for Agro-Scientific Research in the Public Interest, China (201303080)
文摘To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution（50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula） kg–1 straw dry matter, or spraying a large amount of culture broth（1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth） on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter（DM） and crude protein（CP） concentrations, lower neutral detergent fiber（NDF）, acid detergent fiber（ADF） and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM（IVDMD）. The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.
基金supported by the National 863 Program of China(2012AA101803)the National Key Technology R&D Program of China(2012BAD14B06,2012BAD14B01)
文摘This study evaluated the microbial community dynamics and maturation time of two compost systems： biogas slurry compost and cow manure compost, with the aim of evaluating the potential utility of a biogas slurry compost system. Denaturing gradient gel electrophoresis （DGGE）, gene clone library, temperature, C/N ratio, and the germination index were employed for the investigation, cow manure compost was used as the control. Results showed that the basic strip and dominant strips of the DGGE bands for biogas slurry compost were similar to those of cow manure compost, but the brightness of the respective strips for each system were different. Shannon-Weaver indices of the two compost systems differed, possessing only 22% similarity in the primary and maturity stages of the compost process. Using bacterial 16S rRNA gene clone library analysis, 88 bacterial clones were detected. Further, 18 and 13 operational taxonomic units （OTUs） were present in biogas slurry and cow manure compost, respectively. The 18 OTUs of the biogas slurry compost belonged to nine bacterial genera, of which the dominant strains were Bacillus sp. and Carnobacterium sp.; the 13 OTUs of the cow manure compost belonged to eight bacterial genera, of which the dominant strains were Psychrobacter sp., Pseudomonas sp., and Clostridium sp. Results demonstrated that the duration of the thermophilic phase （more than 50°C） for biogas slurry compost was 8 d less than the according duration for cow manure compost, and the maturation times for biogas slurry and cow manure compost were 45 and 60 d, respectively. It is an effective biogas slurry assimilate technology by application of biogas slurry as nitrogen additives in the manufacture of organic fertilizer.
基金supported by the Key Technologies Research and Development Program of China during the11th Five-Year Plan period (2006BAD07A01,2007BAD89B07)the National Commonweal Scientific Research Found (200803033-B0502)the Center College Basic Scientific Research Fund, China(DL09BA31)
文摘In order to study degradation capability and optimal condition of produced endoglucanase （CMCcase）, the microbial community with efficient cellulose degrading ability in 28℃ was studied. Microbial community came from rotted rice straw which was enriched and domesticated by improved Mandels medium. The standard cellulase activity assays were used to determine cellulase activity, degradation products were analyzed by gas chromatography mass spectrometry （GC/MS）, and denaturing gradient gel electrophoresis （DGGE） was used to identify the composition dynamic of the community. The results showed that the microbial community could degrade 39.6% of rice straw gross weight within 6 d. When culture medium volume was 1/5 and pH = 6 on day 5, the CMCcase activity reached the highest of 14 IU mL-L During the fermentation, more than ten products were detected using GCMS. The microbial changed lots in different fermentation periods which detected by DGGE. Phylogenetic tree derived from 16S rDNA sequence found that the community composed of bacteria, and the closest relative were belong to Clostridium sp., Brevibacillus sp. and Bacterium sp. This microbial community could accelerate rice straw rotting and decomposed products could promote organic matter increase of soil
