In Burkina Faso, as in other African countries, infertility has become a social burden for the population and a public health problem. Male infertility accounts for 30% to 40% of all infertility cases. The diagnosis o...In Burkina Faso, as in other African countries, infertility has become a social burden for the population and a public health problem. Male infertility accounts for 30% to 40% of all infertility cases. The diagnosis of male infertility or hypofertility is often made by a simple laboratory analysis of sperm to explore sperm parameters. In most African countries, such as Burkina Faso, microbiological analysis in the context of sperm analysis is still not developed, and is carried out solely based on microscopy and traditional culture, which does not allow the growth of fragile and demanding bacteria. Our study investigated the microorganisms of sperm that may be involved in male infertility, using conventional bacteriology techniques and real-time PCR. However, it did not intend to perform a multivariate statistical association analysis to estimate the association of microorganisms with abnormal semen parameters. This prospective cross-sectional pilot study was carried out on patients who visited the bacteriology laboratory of Centre MURAZ, a research Institute in Burkina Faso, for male infertility diagnosis between 2 August and 31 August 2021. Bacteria were isolated and identified using standard bacteriology techniques. In parallel, common pathogenic microorganisms known to be associated with male infertility were targeted and detected in the sperm using a multiplex real-time PCR assay. A total of 38 sperm samples were analyzed by bacteriological culture and bacteria isolated were Staphylococcus aureus (S. aureus) 5.55%, Klebsiella pneumoniae (K. pneumoniae), Enterococcus faecalis (E. faecalis), Streptococcus agalactiae (S. agalactiae) and Staphylococcus hoemalyticus (S. hoemalyticus) respectively 2.70%. Real-time PCR targeted and detected Chlamydia trachomatis (C. trachomatis) at 7.89%, Ureaplasma urealyticum (U. urealyticum) at 21.05%, Ureaplasma parvum (U. parvum) at 18.42%, Mycoplasma hominis (M. hominis) at 15.79%, Mycoplasma genitalium (M. genitalium) at 10.53% and Trichomonas vaginalis (T. vaginalis) at 2.63%. Neisseria gonorrhoeae (N. gonorrhoeae) was targeted by the real-time PCR assay and was not detected (0%) in the tested semen samples. Our study highlights critical limitations of culture performance (low sensitivity), particularly in Burkina Faso, which has a total inability to detect microorganisms (fragile and demanding microorganisms) detected by PCR-based assays. There is therefore an urgent need to at least optimize culture, procedures and algorithms for detection of microorganisms associated with male infertility in clinical laboratories of Burkina Faso. The most effective solution is the routine implementation of molecular diagnostic methods.展开更多
Background Organic selenium(Se)has gained recognition in poultry nutrition as a feed additive to boost production and Se deposition in eggs and tissues,owing to its high bioavailability,efficient tissue accumulation a...Background Organic selenium(Se)has gained recognition in poultry nutrition as a feed additive to boost production and Se deposition in eggs and tissues,owing to its high bioavailability,efficient tissue accumulation and minimal toxicity.Selenium-enriched yeast(SeY)is a well-established source,while selenium-enriched lactobacilli(SeL),a newer alternative,offers the added benefits of probiotics.This study examined the effects of SeY and SeL on egg quality,antioxidant capacity,Se deposition,and gut health in laying hens.After a two-week pre-treatment with a Sedeficient diet(SeD),450 Hy-Line Brown laying hens(30-week-old)were assigned into five dietary groups with six replicates of 15 hens each.The groups included a SeD,SeD supplemented with 1.5 mg Se/kg from SeY(SeY15),or 1.5,3.0,and 6.0 mg Se/kg from SeL(SeL15,SeL30,SeL60).The feeding trial lasted for 12 weeks.Results SeY15 and SeL15 improved the feed-to-egg ratio(P<0.05)in the latter stages.Haugh units were significantly increased(P<0.05)in the SeY15 and SeL30 groups,while darker yolk color(P<0.05)was observed in the SeY15,SeL15,and SeL60 groups.All Se-supplemented diets increased Se content in whole eggs,albumen,and yolk(P<0.05),while SeL groups showed a dose-dependent effect.Antioxidant enzyme activities increased,and MDA content decreased in the serum(P<0.05),with SeY15 showing the highest GSH-Px levels(P<0.05).SeL60 increased serum alkaline phosphatase and aspartate transaminase,and distorted the liver architecture(P<0.05).Se-diets reduced concentrations of reactive oxygen species(ROS)in the ileum and liver(P<0.05).SeL15 improved the ileal villus height-tocrypt depth ratio(P<0.05).SeY15 and/or SeL15 up-regulated TXNRD1 and SEPHS1 mRNA while down-regulating SCLY expression in the liver.SeY15 altered ileal microbiota by increasing both beneficial and pathogenic bacteria,whereas SeL15 predominantly boosted beneficial bacteria.Conclusion SeL integrates the antioxidant properties of organic Se with the probiotic benefits on gut health,resulting in a performance-enhancing effect comparable to that of SeY.However,high SeL level(6.0 mg Se/kg)compromised productivity and metabolic functions while enhancing Se deposition.展开更多
[Objectives]To systematically investigate the microbial community composition of rhizosphere soil and endophytes associated with Pogostemon cablin,and to explore the relationships between endophytes and rhizosphere mi...[Objectives]To systematically investigate the microbial community composition of rhizosphere soil and endophytes associated with Pogostemon cablin,and to explore the relationships between endophytes and rhizosphere microorganisms as well as their potential applications.[Methods]Microbial isolates were obtained from rhizosphere soil,root tissues,and stem tissues using the serial dilution and spread plate method.These isolates were identified through morphological characterization,physiological and biochemical assays,and molecular biological techniques.[Results]A total of 18 microbial strains were isolated,including 7 bacterial and 11 fungal strains.Among the bacterial isolates,Pseudomonas spp.and Bacillus spp.were predominant,while the fungal isolates were mainly represented by Aspergillus spp.Certain bacterial strains,notably Pseudomonas spp.,exhibited potential abilities for indole-3-acetic acid(IAA)production,nitrogen fixation,and antagonistic activity against pathogenic microorganisms,suggesting their potential utility as biocontrol agents and promoters of plant growth.[Conclusions]This study establishes a foundational understanding of the microbial community characteristics in the rhizosphere and tissues of P.cablin,as well as their roles in plant growth and development.展开更多
[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyi...[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyin 1’as experimental materials,five soil temperature gradients(25,30,35,40,and 45℃)were established.After a 96 d cultivation,soil nutrient content and soil microbial functional diversity were measured to elucidate the impact of high soil temperature on the soil microenvironment.[Results]As soil temperature increased,the contents of total nitrogen,alkaline hydrolyzable nitrogen,available phosphorus,and rapidly available potassium generally showed a decreasing trend.However,under the 45℃ treatment,the contents of total nitrogen,available phosphorus,and rapidly available potassium were the highest among all treatments,although the alkaline hydrolyzable nitrogen content was significantly lower compared to the other treatments.BIOLOG analysis revealed that with increasing soil temperature,the average soil microbial absorbance value and the Shannon diversity index decreased significantly.In contrast,the Shannon evenness index and the Simpson dominance index showed no significant differences across the different temperature treatments.This indicates that as soil temperature rises,the carbon source utilization capacity of the soil microbial community decreases,leading to reduced overall carbon metabolic activity and microbial functional diversity,while the dominant microbial populations remained unchanged during this process.Principal component analysis further confirmed effective separation among the different temperature treatments,suggesting that high soil stress significantly altered the structure of the soil microbial community.[Conclusions]In practical production,appropriate measures should be taken to decrease soil temperature to create a favorable rhizosphere microenvironment and thereby promote crop growth.展开更多
[Objective]The paper was to provide reference for further study and development of gayal（Bos frontalis）.[Method]According to the research status at home and abroad,the biological characteristics and rumen microorgan...[Objective]The paper was to provide reference for further study and development of gayal（Bos frontalis）.[Method]According to the research status at home and abroad,the biological characteristics and rumen microorganisms of gayal in Yunnan Province was studied.[Result]Gayal in Yunnan had typical body form and very good meat production performance,its muscle fiber diameter was significantly less than other kinds of cattle;the water holding ratio,muscle tenderness and muscle succulency were significantly higher than others;its amount,shape and structure of chromosome were different from yellow cattle（Bos taurus）and wild cattle（Bos gaurus）,and the amounts of those chromosomes（2n）were 58,60 and 56,respectively.It could create hybrid with yellow cattle;the gayal＇s special diet was bamboo,its in vitro dry matter digestibility（IVDMD）on various crude forage was significantly higher than yellow cattle in Yunnan;the viable bacteria and cellulolytic bacteria in rumen were 4.51×109 and 1.63×109 CFU/ml,which was significantly higher than yellow cattle in Yunnan,its dominant bacteria in rumen mainly was cellulolytic bacteria.[Conclusion]Gayal not only had high academic value,but also had a great development value.展开更多
Due to its strong and effective insecticidal properties, transgenic Bt＋CpTI cotton has witnessed an expanding planting area in recent years, and the impact of its cultivation on soil ecosystem becomes an important pa...Due to its strong and effective insecticidal properties, transgenic Bt＋CpTI cotton has witnessed an expanding planting area in recent years, and the impact of its cultivation on soil ecosystem becomes an important part of environmental risk assessment. Using transgenic Bt＋CpTI cotton sGK321 and its parental homologous conventional cotton Shiyuan 321 as the study objects, a comparative analysis was conducted on the changes in enzyme activities （urease, alkaline phosphatase, and catalase） of the rhizosphere soil and changes in the number of culturable microor-ganisms （bacteria, fungi, and actinomycetes） at different growth stages （seedling stage, budding stage, flower and bol stage, and bol opening stage） of sGK321 and Shiyuan 321 under the condition of 13 years field plantings. The results showed that, the populations of bacteria, fungi, and actinomycete and the soil enzyme activi-ties of urease, alkaline phosphatase and catalase had a similar variation trend along with the cotton growing process for transgenic cotton and conventional cotton. Some occasional and inconsistent effects on soil enzyme activities and soil fungi composi-tion in the rhizosphere soil of transgenic Bt＋CpTI cotton were found at the seedling stage, budding stage, flower and bol stage as compared with that of conventional cotton. The amount of bacteria and actinomycetes were not significantly different during a certain stage; however, the activities of urease, catalase, alkaline phos-phatase, also with the number of fungi were significantly different, e.g. the urease activities at seedling stage, the alkaline phosphatase at seedling and budding stages, and the soil culturable fungi at flower and bol stage were less than that of conven-tional cotton, while the soil alkaline phosphatase activities at flower and bol stage were higher. Cluster analysis showed that soil enzyme activities and microbial popu-lation changed mainly along the growth processes, suffering little from the planting of transgenic Bt＋CpTI cotton.展开更多
All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciati...All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C （Cmic）/organic C （Corg） ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.展开更多
Biodegradation of polycyclic aromatic hydrocarbons （PAHs） is very difficult in saline-alkaline soil due to the inhibition of microbial growth under saline-alkaline stress. The microorganisms that can most effectivel...Biodegradation of polycyclic aromatic hydrocarbons （PAHs） is very difficult in saline-alkaline soil due to the inhibition of microbial growth under saline-alkaline stress. The microorganisms that can most effectively degrade PAHs were screened by introducing microorganisms immobilized on farm byproducts and assessing the validity of the immobilizing technique for PAHs degradation in pyrene-contaminated saline-alkaline soil. Among the microorganisms examined, it was found that Mycobacterium sp. B2 is the best, and can degrade 82.2% and 83.2% of pyrene for free and immobilized cells after 30 days of incubation. The immobilization technique could increase the degradation of pyrene significantly, especially for fungi. The degradation of pyrene by the immobilized microorganisms Mucor sp. F2, fungal consortium MF and co-cultures of MB＋MF was increased by 161.7% （P 〈 0.05）, 60.1% （P 〈 0.05） and 59.6% （P 〈 0.05） after 30 days, respectively, when compared with free F2, MF and MB＋ME Scanning electron micrographs of the immobilized microstructure proved the positive effects of the immobilized microbial technique on pyrene remediation in saline- alkaline soil, as the interspace of the carder material structure was relatively large, providing enough space for cell growth. Co-cultures of different bacterial and fungal species showed different abilities to degrade PAHs. The present study suggests that Mycobacterium sp. B2 can be employed for in situ bioremediation of PAHs in saline-alkaline soil, and immobilization of fungi on farm byproducts and nutrients as carriers will enhance fungus PAil-degradation ability in saline-alkaline soil.展开更多
The removal of rare earth elements （REEs） from solution in various microorganisms was examined. Seventy-six strains from 69 species （22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts） were tested. Initially, ...The removal of rare earth elements （REEs） from solution in various microorganisms was examined. Seventy-six strains from 69 species （22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts） were tested. Initially, Sm was used to test the removal capabilities of the various organisms. Gram-positive bacteria, such as Bacillus licheniformis, B. subtilis, Brevibacterium helovolum, and Rhodococcus elythropolis, exhibited a particularly high capacity for accumulating Sm. In particular, the B. lichemiformis cells accumulated approximately 316 μmol Sm per gram dry wt. of microbial cells. A full suite of screenings was then conducted to compare the abilities of the organisms to remove Se, Y, La, Er, and, Lu from solution. Tests were done with solutions containing one REE at a time. Accumulation was nearly identical for the various metals and organisms. However, when solutions with equimolar amounts of two REEs were used, preferential removal from solution was observed. When an Eu/Gd solution was used, gram-positive bacteria removed more Eu and Gd as compared to actinomycetes. When Eu/Sm combination was used, gram-positive bacteria removed equal mounts of both metals and some actinomycetes removed more Eu. The selective removal was quantified by calculating separation factors （S. F.）, which indicated that Streptomyces levoris cells accumulated the greatest proportion of Eu. The removal of REEs from a solution containing five metals （Y, La, Sm, Er, and Lu） was then examined. Mucorjavanicus preferentially accumulated Sm and S. flavoviridis preferentially accumulated Lu. The effects of pH and Sm concentration on the accumulation of Sm by B. licheniformis were also examined. Accumulation increased at higher pH and at greater solution concentrations.展开更多
Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure wit...Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure with 5% sodium chloride in the substrate. In the early period of experiment, coccoid and rode-like bacteria predominated in the yellowish-brown granules, and later the white and the black granules were developed by filamentous microorganisms. The filamentous granules exhibited low porosity and fast settling velocity, and were more compact even than bacteria granules. It was hypothesized that the elevated pH in the later period might be a possible reason for the compact growth of filamentous granules. However, the bacteria granules showed the high bioactivity in terms of specific oxygen utilizing rate, and comprised of a wider diversity of compounds based on the thermogravimetric evaluation. The findings in this study demonstrated that filamentous microbes could form compact granular structure, which may encourage the utilization of filamentous microorganisms rather than the inhibition of their growth, as the latter is frequently used for sludge bulking control.展开更多
Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols. Most previous work has focused on the evaluation of their biological risks. In this study, ho...Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols. Most previous work has focused on the evaluation of their biological risks. In this study, however, the adsorption method was applied to reduce airborne microorganisms generated from a pilot scale wastewater treatment facility with oxidation ditch. Results showed adsorption on granule activated carbon （GAC） was an efficient method for the purification of airborne microorganisms. The GAC itself had a maximum adsorption capacity of 2217 CFU/g for airborne bacteria and 225 CFU/g for fungi with a flow rate of 1.50 m^3/hr. Over 85% of airborne bacteria and fungi emitted from the oxidation ditch were adsorbed within 80 hr of continuous operation mode. Most of them had a particle size of 0.65-4.7 μm. Those airborne microorganisms with small particle size were apt to be adsorbed. The SEM/EDAX, BET and Boehm＇s titration methods were applied to analyse the physicochemical characteristics of the GAC. Relationships between GAC surface characteristics and its adsorption performance demonstrated that porous structure, large surface area, and hydrophobicity rendered GAC an effective absorber of airborne microorganisms. Two regenerate methods, ultraviolet irradiation and high pressure vapor, were compared for the regeneration of used activated carbon. High pressure vapor was an effective technique as it totally destroyed the microorganisms adhered to the activated carbon. Microscopic observation was also carried out to investigate original and used adsorbents.展开更多
The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their...The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their DNA is damaged.The approach applied in this study is to test with COMET assay the damage of EM DNA in wastewater with different concentrations of heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,Zn2+,as well as the effects of EM treated with As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,and Zn2+ on COD degradin...展开更多
The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of...The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.展开更多
Molar-tooth carbonate refers to a sort of rock that has ptygmatical folded structure comparable to the ivory. This kind of carbonate exists in a special time range (from Middle to Neoproterozoic). Its origin and the p...Molar-tooth carbonate refers to a sort of rock that has ptygmatical folded structure comparable to the ivory. This kind of carbonate exists in a special time range (from Middle to Neoproterozoic). Its origin and the possibility to use it in stratigraphic correlation of the paleocontinent is the key task of the IGCP447, a project on Proterozoic molar tooth carbonates and the evolution of the earth (2001-2005). The importance lies in that the molar-tooth structure is the key to solving problems related to Precambrian biological and global geochemical events. The molar-tooth structure is associated with microorganisms. Development and recession of such carbonates have relations with the evolution process of early lives and abrupt changes in sea carbonate geochemistry. In recent years, based on researches on petrology, geochemistry and Sr isotope of molar-tooth carbonate in the Jilin-Liaoning and Xuzhou-Huaiyang area, the authors hold that it can be used as a marker for stratigraphic sequence and sedimentary fades analyses.展开更多
Black soybeans [Glycine max（L.） Merrill] were fermented with various GRAS（generally recognized as safe） microorganisms,including Aspergillus sp.,Bacillus sp.and yeast（Issatchenkia orientalis） at 30°C for 3 ...Black soybeans [Glycine max（L.） Merrill] were fermented with various GRAS（generally recognized as safe） microorganisms,including Aspergillus sp.,Bacillus sp.and yeast（Issatchenkia orientalis） at 30°C for 3 d.The antioxidant contents,including total phenolics and total flavonoids,and the antioxidant activities of 1,1-diphenyl-2-picrylhydrazine（DPPH）,ferric reducing antioxidant power（FRAP） and HO.scavenging were analyzed in preparations of fermented black soybeans.Fermented cultures proved to yield significant levels of antioxidants compared with non-fermented cultures（P 〈 0.05）.Fermented black soybean preparations possessed antioxidant activities could be attributed to the total phenolics and flavonoids present.展开更多
As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing ra...As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment.展开更多
Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal...Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen （TN）, total phosphorus （TP）, and total organic carbon （TOC） in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent cartier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied. Results The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively. Conclusion The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.展开更多
Rhizosphere and nonrhizopshere soils were sampled during corn growth. Total, inorganic phosphate-dissolving and lecithin-mineralizing bacteria, fungi and actinomyctes were determined by plate counting method. Generall...Rhizosphere and nonrhizopshere soils were sampled during corn growth. Total, inorganic phosphate-dissolving and lecithin-mineralizing bacteria, fungi and actinomyctes were determined by plate counting method. Generally, the rhizosphere soil contained around 5 to 100 times more of these bacteria and fungi than the non-rhizosphere soil. However, the actinomycetes in the rhizosphere soil were significantly lower than those in the non-rhizosphere soil. The numbers of these microorganisms didn't significantly change during corn growth in the soils. However, the proportion of the phosphate-dissolving microorganisms in the total changed markedly during corn growth. Generally there were much higher percentages of phosphate-dissolving bacteria and phosphate-dissolving fungi in the rhizosphere soil than the nonrhizosphere soil. More than 90% of the fungi in rhizosphere dissolved inorganic phosphate at the seedling period, but this proportion declined to 20% at the harvesting time. The community of phosphate-dissolving microorganisms also changed during corn growth. Bacillus was dominant in the nonrhizosphere soil. However, in the rhizosphere, Pseudomonas and Enterobacter became predominant. Penicillium and Streptomyces were the main fungi and actinomycetes capable of dissolving phosphate.展开更多
By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were ...By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were studied,and soil productivity was tested with yield and agricultural traits of late rice. The results showed that straw returning with the microbial agent could significantly improve the quantity of bacteria,fungi and actinomyces in soil,enhance the activity of sucrase,urease,catalase and cellulase,and improve the number of grains per spike,setting percentage,thousand seed weight and yield of late rice. The combination of rice straw returning and the microbial agent has a good prospect of application.展开更多
Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out i...Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe （including virus） inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination. Conclusion This process takes advantages of free chlorine＇s quick inactivation of microorganisms and chloramine＇s low disinfection by-product （DBP） yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.展开更多
文摘In Burkina Faso, as in other African countries, infertility has become a social burden for the population and a public health problem. Male infertility accounts for 30% to 40% of all infertility cases. The diagnosis of male infertility or hypofertility is often made by a simple laboratory analysis of sperm to explore sperm parameters. In most African countries, such as Burkina Faso, microbiological analysis in the context of sperm analysis is still not developed, and is carried out solely based on microscopy and traditional culture, which does not allow the growth of fragile and demanding bacteria. Our study investigated the microorganisms of sperm that may be involved in male infertility, using conventional bacteriology techniques and real-time PCR. However, it did not intend to perform a multivariate statistical association analysis to estimate the association of microorganisms with abnormal semen parameters. This prospective cross-sectional pilot study was carried out on patients who visited the bacteriology laboratory of Centre MURAZ, a research Institute in Burkina Faso, for male infertility diagnosis between 2 August and 31 August 2021. Bacteria were isolated and identified using standard bacteriology techniques. In parallel, common pathogenic microorganisms known to be associated with male infertility were targeted and detected in the sperm using a multiplex real-time PCR assay. A total of 38 sperm samples were analyzed by bacteriological culture and bacteria isolated were Staphylococcus aureus (S. aureus) 5.55%, Klebsiella pneumoniae (K. pneumoniae), Enterococcus faecalis (E. faecalis), Streptococcus agalactiae (S. agalactiae) and Staphylococcus hoemalyticus (S. hoemalyticus) respectively 2.70%. Real-time PCR targeted and detected Chlamydia trachomatis (C. trachomatis) at 7.89%, Ureaplasma urealyticum (U. urealyticum) at 21.05%, Ureaplasma parvum (U. parvum) at 18.42%, Mycoplasma hominis (M. hominis) at 15.79%, Mycoplasma genitalium (M. genitalium) at 10.53% and Trichomonas vaginalis (T. vaginalis) at 2.63%. Neisseria gonorrhoeae (N. gonorrhoeae) was targeted by the real-time PCR assay and was not detected (0%) in the tested semen samples. Our study highlights critical limitations of culture performance (low sensitivity), particularly in Burkina Faso, which has a total inability to detect microorganisms (fragile and demanding microorganisms) detected by PCR-based assays. There is therefore an urgent need to at least optimize culture, procedures and algorithms for detection of microorganisms associated with male infertility in clinical laboratories of Burkina Faso. The most effective solution is the routine implementation of molecular diagnostic methods.
基金supported by the National Natural Science Foundation of China(32302774)Beijing Innovation Consortium of Agriculture Research System(BAIC04)+1 种基金China Agriculture Research System(CARS-40)the Agricultural Science and Technology Innovation Program of the Feed Research Institute of the Chinese Academy of Agricultural Sciences(CAASIFR-ZDRW202402).
文摘Background Organic selenium(Se)has gained recognition in poultry nutrition as a feed additive to boost production and Se deposition in eggs and tissues,owing to its high bioavailability,efficient tissue accumulation and minimal toxicity.Selenium-enriched yeast(SeY)is a well-established source,while selenium-enriched lactobacilli(SeL),a newer alternative,offers the added benefits of probiotics.This study examined the effects of SeY and SeL on egg quality,antioxidant capacity,Se deposition,and gut health in laying hens.After a two-week pre-treatment with a Sedeficient diet(SeD),450 Hy-Line Brown laying hens(30-week-old)were assigned into five dietary groups with six replicates of 15 hens each.The groups included a SeD,SeD supplemented with 1.5 mg Se/kg from SeY(SeY15),or 1.5,3.0,and 6.0 mg Se/kg from SeL(SeL15,SeL30,SeL60).The feeding trial lasted for 12 weeks.Results SeY15 and SeL15 improved the feed-to-egg ratio(P<0.05)in the latter stages.Haugh units were significantly increased(P<0.05)in the SeY15 and SeL30 groups,while darker yolk color(P<0.05)was observed in the SeY15,SeL15,and SeL60 groups.All Se-supplemented diets increased Se content in whole eggs,albumen,and yolk(P<0.05),while SeL groups showed a dose-dependent effect.Antioxidant enzyme activities increased,and MDA content decreased in the serum(P<0.05),with SeY15 showing the highest GSH-Px levels(P<0.05).SeL60 increased serum alkaline phosphatase and aspartate transaminase,and distorted the liver architecture(P<0.05).Se-diets reduced concentrations of reactive oxygen species(ROS)in the ileum and liver(P<0.05).SeL15 improved the ileal villus height-tocrypt depth ratio(P<0.05).SeY15 and/or SeL15 up-regulated TXNRD1 and SEPHS1 mRNA while down-regulating SCLY expression in the liver.SeY15 altered ileal microbiota by increasing both beneficial and pathogenic bacteria,whereas SeL15 predominantly boosted beneficial bacteria.Conclusion SeL integrates the antioxidant properties of organic Se with the probiotic benefits on gut health,resulting in a performance-enhancing effect comparable to that of SeY.However,high SeL level(6.0 mg Se/kg)compromised productivity and metabolic functions while enhancing Se deposition.
基金Supported by Rural Science and Technology Commissioner Project of Guangdong Province(KTP20240806).
文摘[Objectives]To systematically investigate the microbial community composition of rhizosphere soil and endophytes associated with Pogostemon cablin,and to explore the relationships between endophytes and rhizosphere microorganisms as well as their potential applications.[Methods]Microbial isolates were obtained from rhizosphere soil,root tissues,and stem tissues using the serial dilution and spread plate method.These isolates were identified through morphological characterization,physiological and biochemical assays,and molecular biological techniques.[Results]A total of 18 microbial strains were isolated,including 7 bacterial and 11 fungal strains.Among the bacterial isolates,Pseudomonas spp.and Bacillus spp.were predominant,while the fungal isolates were mainly represented by Aspergillus spp.Certain bacterial strains,notably Pseudomonas spp.,exhibited potential abilities for indole-3-acetic acid(IAA)production,nitrogen fixation,and antagonistic activity against pathogenic microorganisms,suggesting their potential utility as biocontrol agents and promoters of plant growth.[Conclusions]This study establishes a foundational understanding of the microbial community characteristics in the rhizosphere and tissues of P.cablin,as well as their roles in plant growth and development.
基金Supported by Natural Science Foundation of Hainan Province(320MS108)Scientific and Technological Innovation Team of the National Center for Tropical Agricultural Science,Chinese Academy of Tropical Agricultural Sciences(CATASCXTD202303)Key Laboratory of Genetic Resources Utilization of Spice and Beverage Crops,Ministry of Agriculture and Rural Affairs,Hainan Provincial Key Laboratory of Genetic Improvement and Quality Regulation for Tropical Spice and Beverage Crops,or Hainan Provincial Engineering Research Center for Tropical Spice and Beverage Crops(2019xys007).
文摘[Objectives]To explore the effects of high soil temperature stress on microorganisms utilizing different carbon sources in the rhizosphere of pepper seedlings.[Methods]Using seedlings of the main pepper cultivar‘Reyin 1’as experimental materials,five soil temperature gradients(25,30,35,40,and 45℃)were established.After a 96 d cultivation,soil nutrient content and soil microbial functional diversity were measured to elucidate the impact of high soil temperature on the soil microenvironment.[Results]As soil temperature increased,the contents of total nitrogen,alkaline hydrolyzable nitrogen,available phosphorus,and rapidly available potassium generally showed a decreasing trend.However,under the 45℃ treatment,the contents of total nitrogen,available phosphorus,and rapidly available potassium were the highest among all treatments,although the alkaline hydrolyzable nitrogen content was significantly lower compared to the other treatments.BIOLOG analysis revealed that with increasing soil temperature,the average soil microbial absorbance value and the Shannon diversity index decreased significantly.In contrast,the Shannon evenness index and the Simpson dominance index showed no significant differences across the different temperature treatments.This indicates that as soil temperature rises,the carbon source utilization capacity of the soil microbial community decreases,leading to reduced overall carbon metabolic activity and microbial functional diversity,while the dominant microbial populations remained unchanged during this process.Principal component analysis further confirmed effective separation among the different temperature treatments,suggesting that high soil stress significantly altered the structure of the soil microbial community.[Conclusions]In practical production,appropriate measures should be taken to decrease soil temperature to create a favorable rhizosphere microenvironment and thereby promote crop growth.
基金Supported by National Natural Science Foundation of China(30960256,31060314)Project of Yunnan Education Department(V09Y0202)~~
文摘[Objective]The paper was to provide reference for further study and development of gayal（Bos frontalis）.[Method]According to the research status at home and abroad,the biological characteristics and rumen microorganisms of gayal in Yunnan Province was studied.[Result]Gayal in Yunnan had typical body form and very good meat production performance,its muscle fiber diameter was significantly less than other kinds of cattle;the water holding ratio,muscle tenderness and muscle succulency were significantly higher than others;its amount,shape and structure of chromosome were different from yellow cattle（Bos taurus）and wild cattle（Bos gaurus）,and the amounts of those chromosomes（2n）were 58,60 and 56,respectively.It could create hybrid with yellow cattle;the gayal＇s special diet was bamboo,its in vitro dry matter digestibility（IVDMD）on various crude forage was significantly higher than yellow cattle in Yunnan;the viable bacteria and cellulolytic bacteria in rumen were 4.51×109 and 1.63×109 CFU/ml,which was significantly higher than yellow cattle in Yunnan,its dominant bacteria in rumen mainly was cellulolytic bacteria.[Conclusion]Gayal not only had high academic value,but also had a great development value.
文摘Due to its strong and effective insecticidal properties, transgenic Bt＋CpTI cotton has witnessed an expanding planting area in recent years, and the impact of its cultivation on soil ecosystem becomes an important part of environmental risk assessment. Using transgenic Bt＋CpTI cotton sGK321 and its parental homologous conventional cotton Shiyuan 321 as the study objects, a comparative analysis was conducted on the changes in enzyme activities （urease, alkaline phosphatase, and catalase） of the rhizosphere soil and changes in the number of culturable microor-ganisms （bacteria, fungi, and actinomycetes） at different growth stages （seedling stage, budding stage, flower and bol stage, and bol opening stage） of sGK321 and Shiyuan 321 under the condition of 13 years field plantings. The results showed that, the populations of bacteria, fungi, and actinomycete and the soil enzyme activi-ties of urease, alkaline phosphatase and catalase had a similar variation trend along with the cotton growing process for transgenic cotton and conventional cotton. Some occasional and inconsistent effects on soil enzyme activities and soil fungi composi-tion in the rhizosphere soil of transgenic Bt＋CpTI cotton were found at the seedling stage, budding stage, flower and bol stage as compared with that of conventional cotton. The amount of bacteria and actinomycetes were not significantly different during a certain stage; however, the activities of urease, catalase, alkaline phos-phatase, also with the number of fungi were significantly different, e.g. the urease activities at seedling stage, the alkaline phosphatase at seedling and budding stages, and the soil culturable fungi at flower and bol stage were less than that of conven-tional cotton, while the soil alkaline phosphatase activities at flower and bol stage were higher. Cluster analysis showed that soil enzyme activities and microbial popu-lation changed mainly along the growth processes, suffering little from the planting of transgenic Bt＋CpTI cotton.
基金Project supported by the National Natural Science Foundation of Chi-na (No. 40432004, 40601086) the Natural Science Foundationof Zhejiang Province (No. Y504109).
文摘All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C （Cmic）/organic C （Corg） ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.
基金supported by the National Science Foundation of China(No.41101295)the Natural Science Fund Project of Liaoning Province(No.201102226)+1 种基金the Open Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering(MOE)(No.KLIEEE-09-04)the Key Program of National Science Foundation of China(No.40930739)
文摘Biodegradation of polycyclic aromatic hydrocarbons （PAHs） is very difficult in saline-alkaline soil due to the inhibition of microbial growth under saline-alkaline stress. The microorganisms that can most effectively degrade PAHs were screened by introducing microorganisms immobilized on farm byproducts and assessing the validity of the immobilizing technique for PAHs degradation in pyrene-contaminated saline-alkaline soil. Among the microorganisms examined, it was found that Mycobacterium sp. B2 is the best, and can degrade 82.2% and 83.2% of pyrene for free and immobilized cells after 30 days of incubation. The immobilization technique could increase the degradation of pyrene significantly, especially for fungi. The degradation of pyrene by the immobilized microorganisms Mucor sp. F2, fungal consortium MF and co-cultures of MB＋MF was increased by 161.7% （P 〈 0.05）, 60.1% （P 〈 0.05） and 59.6% （P 〈 0.05） after 30 days, respectively, when compared with free F2, MF and MB＋ME Scanning electron micrographs of the immobilized microstructure proved the positive effects of the immobilized microbial technique on pyrene remediation in saline- alkaline soil, as the interspace of the carder material structure was relatively large, providing enough space for cell growth. Co-cultures of different bacterial and fungal species showed different abilities to degrade PAHs. The present study suggests that Mycobacterium sp. B2 can be employed for in situ bioremediation of PAHs in saline-alkaline soil, and immobilization of fungi on farm byproducts and nutrients as carriers will enhance fungus PAil-degradation ability in saline-alkaline soil.
基金This work was supported by the Japan Oil, Gas and Metals National Corporation (JOGMEC)
文摘The removal of rare earth elements （REEs） from solution in various microorganisms was examined. Seventy-six strains from 69 species （22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts） were tested. Initially, Sm was used to test the removal capabilities of the various organisms. Gram-positive bacteria, such as Bacillus licheniformis, B. subtilis, Brevibacterium helovolum, and Rhodococcus elythropolis, exhibited a particularly high capacity for accumulating Sm. In particular, the B. lichemiformis cells accumulated approximately 316 μmol Sm per gram dry wt. of microbial cells. A full suite of screenings was then conducted to compare the abilities of the organisms to remove Se, Y, La, Er, and, Lu from solution. Tests were done with solutions containing one REE at a time. Accumulation was nearly identical for the various metals and organisms. However, when solutions with equimolar amounts of two REEs were used, preferential removal from solution was observed. When an Eu/Gd solution was used, gram-positive bacteria removed more Eu and Gd as compared to actinomycetes. When Eu/Sm combination was used, gram-positive bacteria removed equal mounts of both metals and some actinomycetes removed more Eu. The selective removal was quantified by calculating separation factors （S. F.）, which indicated that Streptomyces levoris cells accumulated the greatest proportion of Eu. The removal of REEs from a solution containing five metals （Y, La, Sm, Er, and Lu） was then examined. Mucorjavanicus preferentially accumulated Sm and S. flavoviridis preferentially accumulated Lu. The effects of pH and Sm concentration on the accumulation of Sm by B. licheniformis were also examined. Accumulation increased at higher pH and at greater solution concentrations.
基金supported by the National Natural Science Foundation of China (No.50708089)the Program for Changjiang Scholars and Innovative Research Team in University of MOE of China (PCSIRT) (No.IRT0853)+1 种基金the Natural Science Foundation of Shaanxi Province (No.2009JQ7002)the Research Plant for Key Laboratoryof Universities of Shaanxi Province (No.09JS027)
文摘Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure with 5% sodium chloride in the substrate. In the early period of experiment, coccoid and rode-like bacteria predominated in the yellowish-brown granules, and later the white and the black granules were developed by filamentous microorganisms. The filamentous granules exhibited low porosity and fast settling velocity, and were more compact even than bacteria granules. It was hypothesized that the elevated pH in the later period might be a possible reason for the compact growth of filamentous granules. However, the bacteria granules showed the high bioactivity in terms of specific oxygen utilizing rate, and comprised of a wider diversity of compounds based on the thermogravimetric evaluation. The findings in this study demonstrated that filamentous microbes could form compact granular structure, which may encourage the utilization of filamentous microorganisms rather than the inhibition of their growth, as the latter is frequently used for sludge bulking control.
基金supported by the National Natural Science Foundation of China (No.50921064, 50978249)
文摘Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols. Most previous work has focused on the evaluation of their biological risks. In this study, however, the adsorption method was applied to reduce airborne microorganisms generated from a pilot scale wastewater treatment facility with oxidation ditch. Results showed adsorption on granule activated carbon （GAC） was an efficient method for the purification of airborne microorganisms. The GAC itself had a maximum adsorption capacity of 2217 CFU/g for airborne bacteria and 225 CFU/g for fungi with a flow rate of 1.50 m^3/hr. Over 85% of airborne bacteria and fungi emitted from the oxidation ditch were adsorbed within 80 hr of continuous operation mode. Most of them had a particle size of 0.65-4.7 μm. Those airborne microorganisms with small particle size were apt to be adsorbed. The SEM/EDAX, BET and Boehm＇s titration methods were applied to analyse the physicochemical characteristics of the GAC. Relationships between GAC surface characteristics and its adsorption performance demonstrated that porous structure, large surface area, and hydrophobicity rendered GAC an effective absorber of airborne microorganisms. Two regenerate methods, ultraviolet irradiation and high pressure vapor, were compared for the regeneration of used activated carbon. High pressure vapor was an effective technique as it totally destroyed the microorganisms adhered to the activated carbon. Microscopic observation was also carried out to investigate original and used adsorbents.
基金supported by the Hi-Tech Re-search and Development Program(863)of China(No.2006AA06Z378)the National Natural Science Founda-tion of China(No.20777018)the Scientific ResearchItem of Guangxi Province Department of Education of China(No.200608LX109)
文摘The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their DNA is damaged.The approach applied in this study is to test with COMET assay the damage of EM DNA in wastewater with different concentrations of heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,Zn2+,as well as the effects of EM treated with As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,and Zn2+ on COD degradin...
文摘The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.
基金This study was sponsored by the Key Program of International Scientific and Technological Cooperation of Ministry of Science and Technology of China(2001 CB 711002)the National Natural Science Foundation of China(No.4017043)the International Geological Correlation Program(IGCP)project 447.
文摘Molar-tooth carbonate refers to a sort of rock that has ptygmatical folded structure comparable to the ivory. This kind of carbonate exists in a special time range (from Middle to Neoproterozoic). Its origin and the possibility to use it in stratigraphic correlation of the paleocontinent is the key task of the IGCP447, a project on Proterozoic molar tooth carbonates and the evolution of the earth (2001-2005). The importance lies in that the molar-tooth structure is the key to solving problems related to Precambrian biological and global geochemical events. The molar-tooth structure is associated with microorganisms. Development and recession of such carbonates have relations with the evolution process of early lives and abrupt changes in sea carbonate geochemistry. In recent years, based on researches on petrology, geochemistry and Sr isotope of molar-tooth carbonate in the Jilin-Liaoning and Xuzhou-Huaiyang area, the authors hold that it can be used as a marker for stratigraphic sequence and sedimentary fades analyses.
基金supproted by a grant from the Korea Institute of Planning and Evaluation for Technology of Food,Agriculture,Forestry and Fishes (i PET)
文摘Black soybeans [Glycine max（L.） Merrill] were fermented with various GRAS（generally recognized as safe） microorganisms,including Aspergillus sp.,Bacillus sp.and yeast（Issatchenkia orientalis） at 30°C for 3 d.The antioxidant contents,including total phenolics and total flavonoids,and the antioxidant activities of 1,1-diphenyl-2-picrylhydrazine（DPPH）,ferric reducing antioxidant power（FRAP） and HO.scavenging were analyzed in preparations of fermented black soybeans.Fermented cultures proved to yield significant levels of antioxidants compared with non-fermented cultures（P 〈 0.05）.Fermented black soybean preparations possessed antioxidant activities could be attributed to the total phenolics and flavonoids present.
文摘As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment.
基金This work was supported by the National Natural Science Foundation of China (No. 30400346)
文摘Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen （TN）, total phosphorus （TP）, and total organic carbon （TOC） in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent cartier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied. Results The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively. Conclusion The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.
文摘Rhizosphere and nonrhizopshere soils were sampled during corn growth. Total, inorganic phosphate-dissolving and lecithin-mineralizing bacteria, fungi and actinomyctes were determined by plate counting method. Generally, the rhizosphere soil contained around 5 to 100 times more of these bacteria and fungi than the non-rhizosphere soil. However, the actinomycetes in the rhizosphere soil were significantly lower than those in the non-rhizosphere soil. The numbers of these microorganisms didn't significantly change during corn growth in the soils. However, the proportion of the phosphate-dissolving microorganisms in the total changed markedly during corn growth. Generally there were much higher percentages of phosphate-dissolving bacteria and phosphate-dissolving fungi in the rhizosphere soil than the nonrhizosphere soil. More than 90% of the fungi in rhizosphere dissolved inorganic phosphate at the seedling period, but this proportion declined to 20% at the harvesting time. The community of phosphate-dissolving microorganisms also changed during corn growth. Bacillus was dominant in the nonrhizosphere soil. However, in the rhizosphere, Pseudomonas and Enterobacter became predominant. Penicillium and Streptomyces were the main fungi and actinomycetes capable of dissolving phosphate.
基金Supported by National Key Research and Development Program of China(2017YFD0200808)National Key Technology R&D Program in the 11th Five-Year Plan of China(2006BAD02A04)+1 种基金Innovation Foundation for Postgraduates in Jiangxi Province(YC10A056)Free Declaration Project of Jiangxi Agricultural University
文摘By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were studied,and soil productivity was tested with yield and agricultural traits of late rice. The results showed that straw returning with the microbial agent could significantly improve the quantity of bacteria,fungi and actinomyces in soil,enhance the activity of sucrase,urease,catalase and cellulase,and improve the number of grains per spike,setting percentage,thousand seed weight and yield of late rice. The combination of rice straw returning and the microbial agent has a good prospect of application.
基金This work was sponsored by National Natural Science Fundation Committee (No. 50238020).
文摘Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe （including virus） inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process. The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination. Conclusion This process takes advantages of free chlorine＇s quick inactivation of microorganisms and chloramine＇s low disinfection by-product （DBP） yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.
