A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in sha...A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in shake flask and bioreactor.The results show that in the shake flask,the mixture can tolerate 50 g/L chalcopyrite after being acclimated to gradually increased concentrations of chalcopyrite.The copper extraction increases obviously in bioleaching of chalcopyrite with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min,74% copper can be extracted in the pulp of 50 g/L chalcopyrite after 20 d.Compared with copper extractions of mesophilic culture,unacclimated culture and acclimated culture without addition of yeast extract,that of accliniated culture with addition of yeast extract is increased by 53%,44% and 16%,respectively.In a completely stirred tank reactor,the mass fraction of copper and total iron extraction reach up to 81% and 56%,respectively.The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from chalcopyrite effectively.展开更多
Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with m...Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.展开更多
In this study,we considered the three-dimensional flow of a rotating viscous,incompressible electrically conducting nanofluid with oxytactic microorganisms and an insulated plate floating in the fluid.Three scenarios ...In this study,we considered the three-dimensional flow of a rotating viscous,incompressible electrically conducting nanofluid with oxytactic microorganisms and an insulated plate floating in the fluid.Three scenarios were considered in this study.The first case is when the fluid drags the plate,the second is when the plate drags the fluid and the third is when the plate floats on the fluid at the same velocity.The denser microorganisms create the bioconvection as they swim to the top following an oxygen gradient within the fluid.The velocity ratio parameter plays a key role in the dynamics for this flow.Varying the parameter below and above a critical value alters the dynamics of the flow.The Hartmann number,buoyancy ratio and radiation parameter have a reverse effect on the secondary velocity for values of the velocity ratio above and below the critical value.The Hall parameter on the other hand has a reverse effect on the primary velocity for values of velocity ratio above and below the critical value.The bioconvection Rayleigh number decreases the primary velocity.The secondary velocity increases with increasing values of the bioconvection Rayleigh number and is positive for velocity ratio values below 0.5.For values of the velocity ratio parameter above 0.5,the secondary velocity is negative for small values of bioconvection Rayleigh number and as the values increase,the flow is reversed and becomes positive.展开更多
By conducting experimental measurements and numerical simulations of air distribution and microorganism pollutant distribution in the auditorium and game area in a gymnasium,pollutant dispersion control and indoor air...By conducting experimental measurements and numerical simulations of air distribution and microorganism pollutant distribution in the auditorium and game area in a gymnasium,pollutant dispersion control and indoor air quality improvement methods were put forward. The results show that the fungi and bacteria concentration levels are less than the magnitude of 103 CFU (colony-forming units) which meets the requirements of indoor air quality standard. The numerical simulation results quantitatively agree with the experimental data while some differences between theoretical data and experimental data exist in air distributions. People number in gymnasium plays an important role in affecting indoor air quality and the environmental parameters attained the standard.展开更多
12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight...12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology.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
A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the p...A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the plates and isolation of the actinomycetes by using selected culture medium. We formulated that most microflora included the dominant actinomycetes in the soil were carried away with the sterilized water in the elutriation procedure, some rare actinomycetes and few other microflora included bacteria were remained in the elutriated sediments, the other microflora were excluded to grew into colonies on the plates by using selective culture medium for actinomycetes in the elutriated sediments. Results showed the supposition. Non-streptomycete actinomycetes were isolated both from black soil samples from Chinese northeast area and compost samples from Chinese central area. Soil fungi in granule were isolated by using the selective conditions to favor fungi. The results showed that the method was effective展开更多
Mechanical activation (MA) is a significant pretreatment technique for enhancing the dissolution of mineral;however, its promotion effect on the role of pyrite during chalcopyrite bioleaching has not been elucidated u...Mechanical activation (MA) is a significant pretreatment technique for enhancing the dissolution of mineral;however, its promotion effect on the role of pyrite during chalcopyrite bioleaching has not been elucidated up to now. In this study, the effect of MA on the role of pyrite on chalcopyrite bioleaching mediated by Acidithiobacillus ferroxidans was investigated by X-ray diffraction, scanning electron microscopy, particle size distribution analysis, and electrochemical measurement. The results showed MA could significantly reduce the minerals particle size, and increase the specific surface area and surface energy of minerals. For example, the d50 of chalcopyrite reduced from 13.40 to 0.31 μm after MA. The copper extraction of mixed MA-chalcopyrite and MA-pyrite system was 63.4%, which exhibited a 51.8% enhancement compared to the non-activated mixed system. Electrochemical experiments identified that the strengthening effect of pyrite on chalcopyrite dissolution was negligible before MA. After MA, the dissolution mechanism of chalcopyrite was not changed, and pyrite could not only provide additional oxidants (acids and iron) but also act as the cathode in the galvanic couple. In this case, the bioleaching of chalcopyrite was accelerated. Therefore, a model of the promotion effect of mechanical activation on the role of pyrite on chalcopyrite bioleaching was proposed.展开更多
Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the biol...Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.展开更多
The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in He...The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg hm-2.展开更多
The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is c...The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is configured between a pair of circular disks filled with Sutterby fluid conveying tiny particles and gyrotactic microorganisms.The impact of Arrhenius kinetics and thermal radiation is also considered in the governing flow.The presented mathematical models are modified into nonlinear ordinary differential equations using the relevant similarity transformations.To compute the numerical solutions of nonlinear ordinary differential equations,the differential transform procedure(DTM)is used.For nonlinear problems,integral transform techniques are more difficult to execute.However,a polynomial solution is obtained as an analytical solution using the differential transform method,which is based on Taylor expansion.To improve the convergence of the formulated mathematical modeling,the Padéapproximation was combined with the differential transformation method.Variations of different dimensionless factors are discussed for velocity,temperature field,concentration distribution,and motile gyrotactic microorganism profile.Torque on both plates is calculated and presented through tables.展开更多
Ferroplasma thermophilum,a sort of extreme acidophilic archaea,which can synthesize intracellular cobalt ferrite nanocrystals,is investigated in this study.The nanocrystals were analyzed with ultrathin sections and tr...Ferroplasma thermophilum,a sort of extreme acidophilic archaea,which can synthesize intracellular cobalt ferrite nanocrystals,is investigated in this study.The nanocrystals were analyzed with ultrathin sections and transmission electron microscope,with the size of 20−60 nm,the number of more than 30 in each cell at average,which indicated that F.thermophilum can synthesize intracellular nanocrystals and also belongs to high-yield nanocrystals-producing strain.Intriguingly,the nanocrystals contain ferrite and cobalt characterized by EDS X-ray analysis,suggesting that both cobalt and ferrite are potentially contributed to the formation of nanocrystals.Moreover,under the different energy source culture conditions of FeSO4 and CuFeS2,the size and the morphology of the nanocrystals are different.It was also found that the higher initial Fe availability leads to an induced synthesis of larger nanocrystals and the lower oxidation-reduction potential(ORP)leads to an induced effect on the synthesis of nanocrystals with abnormal unhomogeneous size,which suggested that the higher initial Fe availability and the lower oxidation-reduction potential lead to a higher uptake efficiency of iron ions of F.thermophilum by iron and ORP gradient culture.展开更多
Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrr...Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.展开更多
Pepper, celery, eggplant and tomato were used as preceding crops to study their effects on the yield, soil microorganism quantity and soil enzyme activities of cucumber. Results showed that four preceding crops all in...Pepper, celery, eggplant and tomato were used as preceding crops to study their effects on the yield, soil microorganism quantity and soil enzyme activities of cucumber. Results showed that four preceding crops all increased soil microorganism quantity in cucumber, but decreased population of Fusarium oxysporum. The effect of pepper was more significant than that of the others Populations of soil bacteria, fungi and actinomyces of pepper treatment were significantly higher than those of the other treatments, except that the populations of fungi had no significant difference with celery and eggplant treatments on 50 days after transplanting, while that of Fusarium oxysporum was fewer than that of the other treatments. The soil microorganism quantity in celery and eggplant treatment was more significant than tomato, but lower population of Fusarium oxysporum. Four preceding crops all increased sol enzyme activities, lnvertase and urease activities of pepper treatment were significantly higher than those of the other treatments, catalase activities of pepper, celery and eggplant treatments were significantly higher than those of tomato and the control treatments All preceding crops remarkably increased cucumber yield, with pepper as the highest. Comparing with the control, cucumber yields of pepper, celery and eggplant treatments increased by 24.9%, 13.6% and 11.9%, respectively. Results suggested that four preceding crops all improved soil microbial ecology and increased cucumber yield. The pepper was the most suitable preceding crop, then followed by celery and eggplant. Tomato had the similar effect as the control.展开更多
Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor(SBR) under the conventional organic loading rate(OLR) condition.Aerobic granules were succes...Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor(SBR) under the conventional organic loading rate(OLR) condition.Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period.Subsequently,the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules.A small amount of fungal granules had no effect on the performance of granular SBR.Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation.The three-dimensional excitation emission matrix(EEM) spectra result shows that the extracellular polymeric substances(EPS) component in both granules has no much difference,whereas the content of EPS in fungal granules is higher than that in bacterial granules.Due to their low bioactivity,the chemical oxidation demand(COD) and NH4-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the SBR.展开更多
基金Project(50621063, 40646029) supported by the National Natural Science Foundation of ChinaProject (2004CB619204) supported by the National Basic Research Program
文摘A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in shake flask and bioreactor.The results show that in the shake flask,the mixture can tolerate 50 g/L chalcopyrite after being acclimated to gradually increased concentrations of chalcopyrite.The copper extraction increases obviously in bioleaching of chalcopyrite with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min,74% copper can be extracted in the pulp of 50 g/L chalcopyrite after 20 d.Compared with copper extractions of mesophilic culture,unacclimated culture and acclimated culture without addition of yeast extract,that of accliniated culture with addition of yeast extract is increased by 53%,44% and 16%,respectively.In a completely stirred tank reactor,the mass fraction of copper and total iron extraction reach up to 81% and 56%,respectively.The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from chalcopyrite effectively.
基金Project(50321402)supported by the National Natural Science Foundation of ChinaProject(2004CB619201)supported by the Major State Basic Research and Development Program of China
文摘Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.
文摘In this study,we considered the three-dimensional flow of a rotating viscous,incompressible electrically conducting nanofluid with oxytactic microorganisms and an insulated plate floating in the fluid.Three scenarios were considered in this study.The first case is when the fluid drags the plate,the second is when the plate drags the fluid and the third is when the plate floats on the fluid at the same velocity.The denser microorganisms create the bioconvection as they swim to the top following an oxygen gradient within the fluid.The velocity ratio parameter plays a key role in the dynamics for this flow.Varying the parameter below and above a critical value alters the dynamics of the flow.The Hartmann number,buoyancy ratio and radiation parameter have a reverse effect on the secondary velocity for values of the velocity ratio above and below the critical value.The Hall parameter on the other hand has a reverse effect on the primary velocity for values of velocity ratio above and below the critical value.The bioconvection Rayleigh number decreases the primary velocity.The secondary velocity increases with increasing values of the bioconvection Rayleigh number and is positive for velocity ratio values below 0.5.For values of the velocity ratio parameter above 0.5,the secondary velocity is negative for small values of bioconvection Rayleigh number and as the values increase,the flow is reversed and becomes positive.
基金Project(2006BAJ02A10) supported by the National Key Technologies R & D Program of China
文摘By conducting experimental measurements and numerical simulations of air distribution and microorganism pollutant distribution in the auditorium and game area in a gymnasium,pollutant dispersion control and indoor air quality improvement methods were put forward. The results show that the fungi and bacteria concentration levels are less than the magnitude of 103 CFU (colony-forming units) which meets the requirements of indoor air quality standard. The numerical simulation results quantitatively agree with the experimental data while some differences between theoretical data and experimental data exist in air distributions. People number in gymnasium plays an important role in affecting indoor air quality and the environmental parameters attained the standard.
基金Supported by China National Tobacco Corporation[No.110202101048(LS-08)]Hundred’Level Innovative Talent Foundation of Guizhou Province(No.GCC[2022]028-1,GCC[2023]108)+2 种基金Guizhou Science Technology Foundation(No.ZK[2021]Key036)the National Natural Science Foundation of China(No.32160522)Guizhou Province Applied Technology Research and Development Funding Post-subsidy Project and Guizhou Tobacco Company(No.2020XM03,2020XM22,2024XM06).
文摘12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology.
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.
基金Supported by the Youth Foundation of College of Resources and Environment of Northeast Agricultural University
文摘A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the plates and isolation of the actinomycetes by using selected culture medium. We formulated that most microflora included the dominant actinomycetes in the soil were carried away with the sterilized water in the elutriation procedure, some rare actinomycetes and few other microflora included bacteria were remained in the elutriated sediments, the other microflora were excluded to grew into colonies on the plates by using selective culture medium for actinomycetes in the elutriated sediments. Results showed the supposition. Non-streptomycete actinomycetes were isolated both from black soil samples from Chinese northeast area and compost samples from Chinese central area. Soil fungi in granule were isolated by using the selective conditions to favor fungi. The results showed that the method was effective
基金Project(GZC20233199) supported by the Postdoctoral Fellowship Program of CPSF,ChinaProject(2022YFC2105300) supported by the National Key Research and Development Program of China。
文摘Mechanical activation (MA) is a significant pretreatment technique for enhancing the dissolution of mineral;however, its promotion effect on the role of pyrite during chalcopyrite bioleaching has not been elucidated up to now. In this study, the effect of MA on the role of pyrite on chalcopyrite bioleaching mediated by Acidithiobacillus ferroxidans was investigated by X-ray diffraction, scanning electron microscopy, particle size distribution analysis, and electrochemical measurement. The results showed MA could significantly reduce the minerals particle size, and increase the specific surface area and surface energy of minerals. For example, the d50 of chalcopyrite reduced from 13.40 to 0.31 μm after MA. The copper extraction of mixed MA-chalcopyrite and MA-pyrite system was 63.4%, which exhibited a 51.8% enhancement compared to the non-activated mixed system. Electrochemical experiments identified that the strengthening effect of pyrite on chalcopyrite dissolution was negligible before MA. After MA, the dissolution mechanism of chalcopyrite was not changed, and pyrite could not only provide additional oxidants (acids and iron) but also act as the cathode in the galvanic couple. In this case, the bioleaching of chalcopyrite was accelerated. Therefore, a model of the promotion effect of mechanical activation on the role of pyrite on chalcopyrite bioleaching was proposed.
文摘Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.
文摘The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg hm-2.
文摘The primary goal of this study is to examine the flow of non-Newtonian Sutterby fluid conveying tiny particles as well as the induced magnetic field in the involvement of motile gyrotactic microorganisms.The flow is configured between a pair of circular disks filled with Sutterby fluid conveying tiny particles and gyrotactic microorganisms.The impact of Arrhenius kinetics and thermal radiation is also considered in the governing flow.The presented mathematical models are modified into nonlinear ordinary differential equations using the relevant similarity transformations.To compute the numerical solutions of nonlinear ordinary differential equations,the differential transform procedure(DTM)is used.For nonlinear problems,integral transform techniques are more difficult to execute.However,a polynomial solution is obtained as an analytical solution using the differential transform method,which is based on Taylor expansion.To improve the convergence of the formulated mathematical modeling,the Padéapproximation was combined with the differential transformation method.Variations of different dimensionless factors are discussed for velocity,temperature field,concentration distribution,and motile gyrotactic microorganism profile.Torque on both plates is calculated and presented through tables.
基金Project(2018JJ1041)supported by the Natural Science Foundation of Hunan,ChinaProjects(51774332,51934009,U1932129)supported by the National Natural Science Foundation of China。
文摘Ferroplasma thermophilum,a sort of extreme acidophilic archaea,which can synthesize intracellular cobalt ferrite nanocrystals,is investigated in this study.The nanocrystals were analyzed with ultrathin sections and transmission electron microscope,with the size of 20−60 nm,the number of more than 30 in each cell at average,which indicated that F.thermophilum can synthesize intracellular nanocrystals and also belongs to high-yield nanocrystals-producing strain.Intriguingly,the nanocrystals contain ferrite and cobalt characterized by EDS X-ray analysis,suggesting that both cobalt and ferrite are potentially contributed to the formation of nanocrystals.Moreover,under the different energy source culture conditions of FeSO4 and CuFeS2,the size and the morphology of the nanocrystals are different.It was also found that the higher initial Fe availability leads to an induced synthesis of larger nanocrystals and the lower oxidation-reduction potential(ORP)leads to an induced effect on the synthesis of nanocrystals with abnormal unhomogeneous size,which suggested that the higher initial Fe availability and the lower oxidation-reduction potential lead to a higher uptake efficiency of iron ions of F.thermophilum by iron and ORP gradient culture.
基金Project(2010CB630903) supported by the National Basic Research Program of ChinaProject(51374249) supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.
基金Supported by National High Technology Research and Development Program of China (863Program)(2008BADA6B02)National Quantity Vegetable Industry System
文摘Pepper, celery, eggplant and tomato were used as preceding crops to study their effects on the yield, soil microorganism quantity and soil enzyme activities of cucumber. Results showed that four preceding crops all increased soil microorganism quantity in cucumber, but decreased population of Fusarium oxysporum. The effect of pepper was more significant than that of the others Populations of soil bacteria, fungi and actinomyces of pepper treatment were significantly higher than those of the other treatments, except that the populations of fungi had no significant difference with celery and eggplant treatments on 50 days after transplanting, while that of Fusarium oxysporum was fewer than that of the other treatments. The soil microorganism quantity in celery and eggplant treatment was more significant than tomato, but lower population of Fusarium oxysporum. Four preceding crops all increased sol enzyme activities, lnvertase and urease activities of pepper treatment were significantly higher than those of the other treatments, catalase activities of pepper, celery and eggplant treatments were significantly higher than those of tomato and the control treatments All preceding crops remarkably increased cucumber yield, with pepper as the highest. Comparing with the control, cucumber yields of pepper, celery and eggplant treatments increased by 24.9%, 13.6% and 11.9%, respectively. Results suggested that four preceding crops all improved soil microbial ecology and increased cucumber yield. The pepper was the most suitable preceding crop, then followed by celery and eggplant. Tomato had the similar effect as the control.
基金Project(51078036) supported by the National Natural Science Foundation of China
文摘Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor(SBR) under the conventional organic loading rate(OLR) condition.Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period.Subsequently,the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules.A small amount of fungal granules had no effect on the performance of granular SBR.Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation.The three-dimensional excitation emission matrix(EEM) spectra result shows that the extracellular polymeric substances(EPS) component in both granules has no much difference,whereas the content of EPS in fungal granules is higher than that in bacterial granules.Due to their low bioactivity,the chemical oxidation demand(COD) and NH4-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the SBR.
