Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that...Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that most of the strains were Bacillus genera, and six of the 29 strains were bigger than 10 mm of diameter of clear zones. For them, two strains were isolated from rumen fluid(L5 and L7) and other two were isolated from rumen residue(N5 and N9), while others were isolated from soil(T1) and diet(S6), respectively. Strains from rumen fluid and residue had higher activities of FPCase and CMCase, but lower β-glucosidases.展开更多
Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different m...Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.展开更多
A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflo...A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.展开更多
Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen aft...Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment. Treatment effect of anaerobic ammonium oxidation （anammox） process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%, 74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. Thc,dcmand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the inftuent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.展开更多
In the present study,mRNA levels of the ArcA gene of Actinobacillus pleuropneumoniae serotype1 were measured during response to stress by growing under anaerobic conditions.Expression levels were measured by semi-quan...In the present study,mRNA levels of the ArcA gene of Actinobacillus pleuropneumoniae serotype1 were measured during response to stress by growing under anaerobic conditions.Expression levels were measured by semi-quantitative RT-PCR using the housekeeping gene recF as an internal standard.The expression of ArcA was undetectable until about 3 hours under standard culture conditions,but it was promptly and highly expressed in anaerobic culture.The results are consistent with ArcA being a potential virulence gene of Actinobacillus pleuropneumoniae,and likely playing an important role in pathogenesis caused by this organism.展开更多
The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the ga...The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the gas production rate during the digestion process were presented,and the optimal adding concentration of EMs was determined by comparing the reduction effectiveness of septic sludge. The results show that proper addition of EMs can enhance acid buffering capacity of the system,and the NH3-N concentration is lower than inhibition concentration of 2 g/L reported in the literature and maintain the range of pH value which is suitable for both hydrolysis-acidification and methanogenesis. However,overdose of EMs can reduce the initial pH value of septic sludge and decrease the effects of the anaerobic digestion. EMs can increase the quantity of microbe in septic sludge and improve the gas production and generation rate over a period of time. But overdosing EMs can lead to low pH,restrain activity of methanogenic bacteria and affect the quantity and the generation rate of gas. Adding 0.01% EMs achieves the highest sludge reduction with the removal rates of TS,VS and COD by 32.51%,42.34% and 40.97%,respectively.展开更多
The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hyd...The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.展开更多
This article, based on investigation and analysis, existed anaerobic fermentation equipment, with a view to the production of high-latitude area, pointed out the thought of exploiting efficient anaerobic fermentation ...This article, based on investigation and analysis, existed anaerobic fermentation equipment, with a view to the production of high-latitude area, pointed out the thought of exploiting efficient anaerobic fermentation equipment, including： the settting independent equipment of acidogenic phase and methanogenic phase; the applying conbination of AF and UASB in methanogenic phase; adopting efficient sludge inverse flowing equipment and the technique of flora enrichment, and efficient method of saving energy and thermal retardation; adopting autocontrol which could make the equipment run efficiently and stably.展开更多
Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,...Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.展开更多
为研究消毒剂对猪粪厌氧发酵系统的影响,选取不同浓度(质量分数0.02%、0.1%、0.5%)卫可(Virkon^(TM))消毒剂进行试验。结果表明:在高浓度Virkon^(TM)胁迫下,厌氧发酵系统出水中总氮(total nitrogen,TN)、氨氮(ammonia nitrogen,NH_(4)^(...为研究消毒剂对猪粪厌氧发酵系统的影响,选取不同浓度(质量分数0.02%、0.1%、0.5%)卫可(Virkon^(TM))消毒剂进行试验。结果表明:在高浓度Virkon^(TM)胁迫下,厌氧发酵系统出水中总氮(total nitrogen,TN)、氨氮(ammonia nitrogen,NH_(4)^(+)-N)、总磷(total phosphorus,TP)和化学需氧量(chemical oxygen demand,COD)等含量异常剧增,伴随TS和VS的降解率下降。对照组(CK组)和0.02%、0.1%和0.5%Virkon^(TM)试验组(分别记为L组、M组和H组)的最大产CH_(4)速率分别为63.20、71.63、73.10和38.17mL/g且CH_4总产量分别降低4.48%、16.58%(P<0.001)和86.33%(P<0.001)。随着暴露时间的延长,试验组的关键酶活呈先升后降趋势,其中,H组的S-α-GC、S-β-GC、S-ACP、S-NP及S-CAT等土壤酶活被显著性抑制(P<0.05)。进一步结合高通量测序发现,在整个厌氧发酵阶段,H组Ace指数、Chao指数和Shannon指数均显著性低于CK组(P<0.01)。在门水平上,第一优势菌群为厚壁菌门,其次为变形菌门,其中厚壁菌门相对丰度随Virkon^(TM)浓度的上升而降低,而变形菌门则相反;在属水平上,随着厌氧发酵时间的延长,束毛球菌属(Trichococcus)相对丰度均出现不同程度上升,由0.19%~0.39%提升至2.80%~4.20%,而H组中史密斯氏菌属(Smithella)的相对丰度受到极显著性(P<0.001)的抑制,较CK组下降91%。同时通过PICRUSt2功能预测分析发现,各试验组微生物群落COG(clusters of orthologous groups of proteins)功能组成结构差异并不明显,未知功能及氨基酸运输和代谢为主要优势功能;结合KO(KEGG orthology)结果与KEGG(kyoto encyclopedia of genes and genomes)数据库相关基因分析发现,高浓度Virkon^(TM)显著抑制微生物群落的生长代谢活性并削弱厌氧发酵系统的甲烷合成效能,另一方面,却诱导关键功能基因K00531(anfG)的表达活性发生超量级响应,较对照组(CK)激增约272倍。其表达水平的显著上调可能通过强化关键酶活性,使系统对Virkon^(TM)消毒副产物中典型氯代污染物(氯代烷烃及氯代烯烃类化合物)的降解效率获得提升,结果可为猪粪厌氧消化处理提供参考。展开更多
基金Supported by Northeast Agricultural University Innovation Funding for Postgraduate(yjscx14007)China Agriculture Research System(CARS-37)
文摘Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that most of the strains were Bacillus genera, and six of the 29 strains were bigger than 10 mm of diameter of clear zones. For them, two strains were isolated from rumen fluid(L5 and L7) and other two were isolated from rumen residue(N5 and N9), while others were isolated from soil(T1) and diet(S6), respectively. Strains from rumen fluid and residue had higher activities of FPCase and CMCase, but lower β-glucosidases.
基金Supported by the Natural Science Foundation of Heilongjiang Province(QC2014C031)Returned Overseas Foundation of Heilongjiang Province(LC2013C07)+2 种基金Outstanding Academic Leaders Foundation of Harbin City(2013RFXYJ015)Young Reserve Talent Foundation of Harbin City(2014RFQYJ141)Outstanding Young Foundation of Heilongjiang Academy of Agricultural Sciences(2013JCQN003)
文摘Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.
文摘A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.
基金Project (20377013) supported by the National Natural Science Foundation of China project (020959) supported by Department of Science and Technology of Guangdong Province
文摘Large amounts of ammonium and a low content of biodegradable chemical oxygen demand（COD） are contained in leachate from aged landfills, together with the effluent containing high concentration of nitric nitrogen after biochemical treatment. Treatment effect of anaerobic ammonium oxidation （anammox） process on the mixture of the leachate and its biochemical effluent was investigated. The results show that the average removal efficiencies of ammonium, nitric nitrogen and total nitrogen are 87.51%, 74.95% and 79.59%, respectively, corresponding to the average ratio of removed nitric nitrogen to ammonium, i.e. 1.14 during the steady phase of anammox activity. The mean removal efficiency of COD is only 24.01% during the experimental period. Thc,dcmand of total phosphorous for the anammox process is unobvious. Especially, the alkalinity and pH value of the effluent are close to those of the inftuent during the steady phase of anammox activity. In addition, it is demonstrated that the status of the anammox bioreactor can be indicated by the alkalinity and pH value during the course of the experiment. The anammox bioreactor has shown potential for nitrogen removal in the leachate mixture. However, COD and total phosphorous in the leachate mixture need further treatment for removal efficiencies of COD and total phosphorous are not good in the anammox bioreactor.
基金supported by the Biotechnological Key Project of Sichuan Province,China(05NG020-016)The Yangtze River Scholar and Innovation Team develop Project of Ministry of Education,China(IRT0555-9)
文摘In the present study,mRNA levels of the ArcA gene of Actinobacillus pleuropneumoniae serotype1 were measured during response to stress by growing under anaerobic conditions.Expression levels were measured by semi-quantitative RT-PCR using the housekeeping gene recF as an internal standard.The expression of ArcA was undetectable until about 3 hours under standard culture conditions,but it was promptly and highly expressed in anaerobic culture.The results are consistent with ArcA being a potential virulence gene of Actinobacillus pleuropneumoniae,and likely playing an important role in pathogenesis caused by this organism.
基金Project(2008BB7048) supported by Natural Science Foundation of CQ CSTC
文摘The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the gas production rate during the digestion process were presented,and the optimal adding concentration of EMs was determined by comparing the reduction effectiveness of septic sludge. The results show that proper addition of EMs can enhance acid buffering capacity of the system,and the NH3-N concentration is lower than inhibition concentration of 2 g/L reported in the literature and maintain the range of pH value which is suitable for both hydrolysis-acidification and methanogenesis. However,overdose of EMs can reduce the initial pH value of septic sludge and decrease the effects of the anaerobic digestion. EMs can increase the quantity of microbe in septic sludge and improve the gas production and generation rate over a period of time. But overdosing EMs can lead to low pH,restrain activity of methanogenic bacteria and affect the quantity and the generation rate of gas. Adding 0.01% EMs achieves the highest sludge reduction with the removal rates of TS,VS and COD by 32.51%,42.34% and 40.97%,respectively.
文摘The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.
基金Supported by National Natural Sciences Foundation(20040224001)
文摘This article, based on investigation and analysis, existed anaerobic fermentation equipment, with a view to the production of high-latitude area, pointed out the thought of exploiting efficient anaerobic fermentation equipment, including： the settting independent equipment of acidogenic phase and methanogenic phase; the applying conbination of AF and UASB in methanogenic phase; adopting efficient sludge inverse flowing equipment and the technique of flora enrichment, and efficient method of saving energy and thermal retardation; adopting autocontrol which could make the equipment run efficiently and stably.
基金Supported by the Technological Project of Heilongjiang Province"the Open Competition Mechanism to Select the Best Candidates"(2022ZXJ05C01-03)。
文摘Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.
文摘为研究消毒剂对猪粪厌氧发酵系统的影响,选取不同浓度(质量分数0.02%、0.1%、0.5%)卫可(Virkon^(TM))消毒剂进行试验。结果表明:在高浓度Virkon^(TM)胁迫下,厌氧发酵系统出水中总氮(total nitrogen,TN)、氨氮(ammonia nitrogen,NH_(4)^(+)-N)、总磷(total phosphorus,TP)和化学需氧量(chemical oxygen demand,COD)等含量异常剧增,伴随TS和VS的降解率下降。对照组(CK组)和0.02%、0.1%和0.5%Virkon^(TM)试验组(分别记为L组、M组和H组)的最大产CH_(4)速率分别为63.20、71.63、73.10和38.17mL/g且CH_4总产量分别降低4.48%、16.58%(P<0.001)和86.33%(P<0.001)。随着暴露时间的延长,试验组的关键酶活呈先升后降趋势,其中,H组的S-α-GC、S-β-GC、S-ACP、S-NP及S-CAT等土壤酶活被显著性抑制(P<0.05)。进一步结合高通量测序发现,在整个厌氧发酵阶段,H组Ace指数、Chao指数和Shannon指数均显著性低于CK组(P<0.01)。在门水平上,第一优势菌群为厚壁菌门,其次为变形菌门,其中厚壁菌门相对丰度随Virkon^(TM)浓度的上升而降低,而变形菌门则相反;在属水平上,随着厌氧发酵时间的延长,束毛球菌属(Trichococcus)相对丰度均出现不同程度上升,由0.19%~0.39%提升至2.80%~4.20%,而H组中史密斯氏菌属(Smithella)的相对丰度受到极显著性(P<0.001)的抑制,较CK组下降91%。同时通过PICRUSt2功能预测分析发现,各试验组微生物群落COG(clusters of orthologous groups of proteins)功能组成结构差异并不明显,未知功能及氨基酸运输和代谢为主要优势功能;结合KO(KEGG orthology)结果与KEGG(kyoto encyclopedia of genes and genomes)数据库相关基因分析发现,高浓度Virkon^(TM)显著抑制微生物群落的生长代谢活性并削弱厌氧发酵系统的甲烷合成效能,另一方面,却诱导关键功能基因K00531(anfG)的表达活性发生超量级响应,较对照组(CK)激增约272倍。其表达水平的显著上调可能通过强化关键酶活性,使系统对Virkon^(TM)消毒副产物中典型氯代污染物(氯代烷烃及氯代烯烃类化合物)的降解效率获得提升,结果可为猪粪厌氧消化处理提供参考。
