The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that n...The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that non-biological particles, including organic compounds, minerals, and soot, were also visible upon exposure to UV excitation under fluorescence microscope. Using laboratory-prepared biological particles as the control, we investigated the feasibility of identifying both biological and non-biological particles in the same sample with DAPI staining. We prepared biological (bacterial, fungi, and plant detritus) and non-biological (biochar, soot, mineral, metal, fly ash, salt) particles in the laboratory and enumerated the particles and their mixture with DAPI. We found that mineral particles were transparent, and biochar, soot, metals and fly ash particles were black under a filter set at excitation 350/50 nm and emission 460/50 nm bandpass (DAPI-BP), while biological particles were blue, as expected. Particles of the water-soluble salts NaCl and (NH_(4))_(2)SO_(4) were yellow under a filter set at excitation 340–380 nm and emission 425 nm long pass (DAPI-LP). Case studies with samples of dustfall, atmospheric aerosols and surface soils could allow for the quantification of the relative number of different types of particles and particles with organic matter or salt coating as well. Fluorescence enumeration with DAPI stain is thus able to identify the co-existence of biological and non-biological particles in the air, at least to the extent of those examined in this study.展开更多
Performance of biological phosphorus removal in the oxic-settling-anaerobic(OSA) process was investigated. Cell staining and fluorescent in situ hybridization(FISH) were used to analyze characteristics and microbial c...Performance of biological phosphorus removal in the oxic-settling-anaerobic(OSA) process was investigated. Cell staining and fluorescent in situ hybridization(FISH) were used to analyze characteristics and microbial community of sludge. Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system,biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus(TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms(PAOs) . FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system,which accounted for around 28% of total bacteria.展开更多
Biostabilization is a cost-effective method for the beneficial utilization of sewage sludge.However,during the operation of sludge biostabilization,some microbial species could be released into the atmospheric environ...Biostabilization is a cost-effective method for the beneficial utilization of sewage sludge.However,during the operation of sludge biostabilization,some microbial species could be released into the atmospheric environment from the solid-phase of sludge easily and present a high risk to human health.This study aimed to evaluate the risk of bioaerosol during sludge biostabilization.We found a total of nine bacterial phyla,one archaeal phylum,and two fungal phyla in the bioaerosol samples.Among them,Proteobacteria,Actinobacteria,Bacteroidetes,and Ascomycota were the dominant phyla.In addition,the bioaerosolization indexes(BI)of prokaryotic phyla and flingal phyla ranged 0-45 and 0-487,respectively.Mass ilia y Pseudarthrobacter,Pseudomonas,Tremellales spp.,and Fusarium were the preferentially aerosolized microbial genera with maximum bioaerosolization indexes of 19962,10360,1802,3055,and 7398.The bioaerosol concentration during the biostabilization ranged from 160 to 1440 cell/m^(3),and we identified species such as Stenotrophomonas rhizophila and Fusarium graminerum with high bioaerosolization indexes that could be threats to human health.Euryachaeota,which belongs to archaeal phyla,had the highest biostabilization index in our study.We also found that Pseudarthrobacter was the easiest to aerosolize during the sludge biostabilization process.展开更多
基金supports from the Open Fund of Hubei Key Laboratory of Mine Environmental Pollution Control and Remediation(grant No.2014104)the Research Project of Hubei Provincial Department of Education(grant No.D20184502)the National Natural Science Foundation of China(grant No.42107088).
文摘The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that non-biological particles, including organic compounds, minerals, and soot, were also visible upon exposure to UV excitation under fluorescence microscope. Using laboratory-prepared biological particles as the control, we investigated the feasibility of identifying both biological and non-biological particles in the same sample with DAPI staining. We prepared biological (bacterial, fungi, and plant detritus) and non-biological (biochar, soot, mineral, metal, fly ash, salt) particles in the laboratory and enumerated the particles and their mixture with DAPI. We found that mineral particles were transparent, and biochar, soot, metals and fly ash particles were black under a filter set at excitation 350/50 nm and emission 460/50 nm bandpass (DAPI-BP), while biological particles were blue, as expected. Particles of the water-soluble salts NaCl and (NH_(4))_(2)SO_(4) were yellow under a filter set at excitation 340–380 nm and emission 425 nm long pass (DAPI-LP). Case studies with samples of dustfall, atmospheric aerosols and surface soils could allow for the quantification of the relative number of different types of particles and particles with organic matter or salt coating as well. Fluorescence enumeration with DAPI stain is thus able to identify the co-existence of biological and non-biological particles in the air, at least to the extent of those examined in this study.
基金Project (No. 2006BAC19B04) supported by the National Key Technology R&D Program of China
文摘Performance of biological phosphorus removal in the oxic-settling-anaerobic(OSA) process was investigated. Cell staining and fluorescent in situ hybridization(FISH) were used to analyze characteristics and microbial community of sludge. Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system,biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus(TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms(PAOs) . FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system,which accounted for around 28% of total bacteria.
基金the National Key R&D Program of China(No.2018YFD-1100600).
文摘Biostabilization is a cost-effective method for the beneficial utilization of sewage sludge.However,during the operation of sludge biostabilization,some microbial species could be released into the atmospheric environment from the solid-phase of sludge easily and present a high risk to human health.This study aimed to evaluate the risk of bioaerosol during sludge biostabilization.We found a total of nine bacterial phyla,one archaeal phylum,and two fungal phyla in the bioaerosol samples.Among them,Proteobacteria,Actinobacteria,Bacteroidetes,and Ascomycota were the dominant phyla.In addition,the bioaerosolization indexes(BI)of prokaryotic phyla and flingal phyla ranged 0-45 and 0-487,respectively.Mass ilia y Pseudarthrobacter,Pseudomonas,Tremellales spp.,and Fusarium were the preferentially aerosolized microbial genera with maximum bioaerosolization indexes of 19962,10360,1802,3055,and 7398.The bioaerosol concentration during the biostabilization ranged from 160 to 1440 cell/m^(3),and we identified species such as Stenotrophomonas rhizophila and Fusarium graminerum with high bioaerosolization indexes that could be threats to human health.Euryachaeota,which belongs to archaeal phyla,had the highest biostabilization index in our study.We also found that Pseudarthrobacter was the easiest to aerosolize during the sludge biostabilization process.
