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1.
Huan Jing Ke Xue ; 40(5): 2375-2381, 2019 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-31087879

RESUMO

Excessive reclamation leads to rapid degradation of wetland ecosystems. Microbial changes in wetland soils under the influence of human activities can sensitively indicate degradation of soil quality and ecosystem functions. To study the effects of different land use patterns on microbial community structure of wetlands, the Sanjiang Wetland Protected Area of Fuyuan, Heilongjiang Province, was selected as the research area. Soil samples were collected from replanting legume crop area, rice wetland, and primitive peat wetland. Then, the bacterial community structure in the soil was investigated with high-throughput sequencing based on the 16S rRNA gene. The relationship between bacterial community and environmental factors was further explored. The results indicated that, based on the bacterial phylum, there are no significant differences between the microbial community structures of soils under different land use patterns. Nevertheless, at the genus level, higher abundance of Blastocatella, Coxiella, and Rickettsia were detected in the legume rhizospheric soil. In the paddy soil, the relative abundances of Massilia, Nitrosomonas, and Bradyrhizobium are higher, while in the peatand soil, the higher contents are of Rhizomicrobium, Arthrobacter, and Bacillus. The results of Chao1 and Shannon index indicate that the microbial diversity of the paddy soil was higher than in the legume rhizospheric soil and peatland soils. However, no significant differences on bacterial diversity between the legume rhizospheric soil and peatland soils were observed. The results of the correlation analysis indicate that soil reclamation triggers a shift in microbial community mainly because of its influence on soil pH, moisture, and nutrients.


Assuntos
Bactérias/classificação , Microbiota , Microbiologia do Solo , Áreas Alagadas , Agricultura , Biodiversidade , China , Fabaceae , Oryza , RNA Ribossômico 16S , Solo
2.
Sci Rep ; 8(1): 15213, 2018 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-30315269

RESUMO

As the first fungal quorum sensing molecule, farnesol-induced morphological transition is usually studied in dimorphic fungi, but in basidiomycetes the morphological changes regulated by farnesol are rarely investigated. In this study, we found that farnesol made the basidiomycete Coriolus versicolor develop into a hyperbranched morphology with short hyphae and bulbous tips. Farnesol treatment resulted in a significant increase of intracellular oxidative stress level, which influenced the expression of several morphogenesis-related genes, and thereby led to the morphological changes. High oxidative stress level significantly stimulated the expression of laccase genes for improving intracellular laccase biosynthesis. The resulted hyperbranched morphology further accelerated the secretion of intracellular laccase into culture medium. As a result, extracellular laccase production reached a maximum of 2189.2 ± 54.7 U/L in farnesol-induced cultures, which was 6.8-fold greater than that of control cultures. SDS-PAGE and native-PAGE showed that farnesol increased laccase production by promoting the biosynthesis of three laccase isoforms. Together these results provide new opportunities in not only understanding the farnesol-regulated mycelial morphology in basidiomycetes, but also developing novel strategies for enhancing the production of secreted enzymes of biotechnological interest.

3.
Huan Jing Ke Xue ; 38(4): 1327-1339, 2017 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965133

RESUMO

Fine particles(PM2.5) collected by two middle volume air samplers in the suburbs of Baoding and the urban area of Beijing during Jan 10th to 17th, 2015, were used to compare the community characteristics of cultivable bacteria in the two sites. In this study, we observed the particle morphology of PM2.5 using a field emission scanning electron microscope (FESEM), analyzed the air mass transportation source of the two sampling sites by the NOAA/ARL HYSPLIT-4 backward trajectory model, and measured the concentrations of the major water-soluble ions and heavy metal elements in the PM2.5 samples using ion chromatography, continuous flow analyzer and ICP-MS. The results indicated that, the cultivable bacteria of PM2.5 contained three phyla, which were Firmicutes, Actinobacteria and α-Proteobacteria. Nine genera and 17 species of cultivable airborne bacteria were isolated and identified. The most abundant phylum was Firmicutes. The Gram-positive bacteria accounted for more than 90%. The spore-forming Bacillus which was the dominant species contributed 68.15% and 75% to the total bacteria in urban Beijing and the suburbs of Baoding, respectively. The difference in the community structure of PM2.5's cultivable bacteria in the two sampling areas may be affected by PM2.5's physical and chemical properties and air mass transportation.


Assuntos
Microbiologia do Ar , Poluentes Atmosféricos/análise , Bactérias , Monitoramento Ambiental , Pequim , Tamanho da Partícula , Material Particulado
4.
Huan Jing Ke Xue ; 36(9): 3329-38, 2015 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-26717695

RESUMO

Uncontrolled release and arbitrary irrigation reuse of rural wastewater may lead to water pollution, and the microbial pathogens could threaten the safety of freshwater resources and public health. To understand the microbial community structure of rural wastewater and provide the theory for microbial risk assessment of wastewater irrigation, microbial community diversities in the Membrane Bio-Reactor (MBR) process for rural wastewater treatment was studied by terminal restriction fragment length polymorphism (T-RFLP) and 16S rDNA gene clone library. Meanwhile, changes of Arcobacter spp. and total bacteria before and after treatment were detected through real-time quantitative PCR. The clone library results showed that there were 73 positive clones included Proteobacteria (91. 80%), Firmicutes (2. 70%), Bacteroidetes (1. 40%), and uncultured bacteria (4. 10%) in the untreated wastewater. The typical pathogenic genus Arcobacter belonging to e-Proteobacteria was the dominant component of the library, accounting for 68. 5% of all clones. The main groups and their abundance in different treatments were significantly distinct. The highest values of species abundance (S), Shannon-Wiener (H) and Evenness (E) were observed in the adjusting tank, which were 43. 0, 3. 56 and 0. 95, respectively. The real-time quantitative PCR results showed that the copy number of Arcobacter spp. was (1. 09 ± 0. 064 0) x 10(11) copies.L-1 in the untreated sewage, which was consistent with the result of 16S rDNA gene clone library. Compared to untreated wastewater, bacterial copy number in the treated effluent decreased 100 to 1 000 times, respectively, suggesting that MBR treatment system could remove the microbial quantity in such scale. In the recycled water, the physicochemical parameters and indicator bacteria met the water quality standard of farmland irrigation. However, further research is needed to estimate the potential health risks caused by residual pathogenic microorganisms in future.


Assuntos
Bactérias/classificação , Reatores Biológicos/microbiologia , Esgotos/microbiologia , Eliminação de Resíduos Líquidos , Bacteroidetes/classificação , Firmicutes/classificação , Polimorfismo de Fragmento de Restrição , Proteobactérias/classificação , RNA Ribossômico 16S , Purificação da Água
5.
Appl Microbiol Biotechnol ; 98(13): 6137-46, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24687747

RESUMO

An Escherichia coli arsRp::luc-based biosensor was constructed to measure the bioavailability of arsenic (As) in soil. In previous induction experiments, it produced a linear response (R (2) = 0.96, P < 0.01) to As from 0.05 to 5 µmol/L after a 2-h incubation. Then, both chemical sequential extraction, Community Bureau of Reference recommended sequential extraction procedures (BCR-SEPs) and E. coli biosensor, were employed to assess the impact of different long-term fertilization regimes containing N, NP, NPK, M (manure), and NPK + M treatments on the bioavailability of arsenic (As) in soil. Per the BCR-SEPs analysis, the application of M and M + NPK led to a significant (P < 0.01) increase of exchangeable As (2-7 times and 2-5 times, respectively) and reducible As (1.5-2.5 times and 1.5-2.3 times, respectively) compared with the no fertilization treated soil (CK). In addition, direct contact assay of E. coli biosensor with soil particles also supported that bioavailable As in manure-fertilized (M and M + NPK) soil was significantly higher (P < 0.01) than that in CK soil (7 and 9 times, respectively). Organic carbon may be the major factor governing the increase of bioavailable As. More significantly, E. coli biosensor-determined As was only 18.46-85.17 % of exchangeable As and 20.68-90.1 % of reducible As based on BCR-SEPs. In conclusion, NKP fertilization was recommended as a more suitable regime in As-polluted soil especially with high As concentration, and this E. coli arsRp::luc-based biosensor was a more realistic approach in assessing the bioavailability of As in soil since it would not overrate the risk of As to the environment.


Assuntos
Arsênico/análise , Técnicas Biossensoriais/métodos , Técnicas de Química Analítica , Escherichia coli/efeitos dos fármacos , Fertilizantes/estatística & dados numéricos , Poluentes do Solo/análise , Solo/química , Agricultura/métodos , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/genética , Luciferases/análise , Luciferases/genética , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/genética , Transativadores/efeitos dos fármacos , Transativadores/genética
6.
Huan Jing Ke Xue ; 35(1): 327-33, 2014 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-24720223

RESUMO

Cellulose was usually degraded by microbial communities in natural habitats. Construction of a simple cellulolytic consortium is necessary to understand the underlying interaction within microorganisms involved in cellulose conversion. A screening approach was developed to obtain a simple microbial community with the ability of cellulose degradation to methane. This technique was based on the method of enrichment culture accompanying with denaturing gel gradient electrophoresis (DGGE) fingerprint detection technology and roll-tube method. Moreover, a four-strain mixed culture capable of degrading cellulose to methane was isolated from Zoige alpine wetland of the Tibetan Plateau. The results showed that the microbial consortia consisted of three functional groups: the cellulolytic bacterium Clostridium glycolicum, the non-celluloytic bacteria group of Trichococcus flocculiformis and Parabacteroides merdae, and the methanogenic bacterium Methanobacterium subterraneum. This four-strain co-culture can convert cellulose to methane. In the future, the isolated cellulolytic consortia could provide a platform for controlling metabolic pathways and genetic modification involved in methane production from cellulose.


Assuntos
Celulose/metabolismo , Metano/metabolismo , Consórcios Microbianos , Bacteroidetes/metabolismo , Carnobacteriaceae/metabolismo , Clostridium/metabolismo , Técnicas de Cocultura , Eletroforese em Gel de Gradiente Desnaturante , Methanobacterium/metabolismo
7.
Environ Sci Process Impacts ; 16(4): 890-6, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24519239

RESUMO

An Escherichia coli cadAp::luc-based whole-cell sensor was constructed to measure cadmium (Cd) bioavailability and assess the immobilizing efficiency of phosphate and silicate on Cd. In previous induction experiments, a linear response (R(2) = 0.97, P < 0.01) from 0.1 to 5 µmol L(-1) of Cd was detected by this sensor after a 2 h incubation. The sensor was then used to estimate Cd bioavailability in soils spiked with different amounts of dipotassium phosphate (DKP, K2HPO4) or sodium silicate (SS, Na2SiO3·9H2O). The total Cd in soil-water extracts (TSWE) was determined with ICP-MS, and the bioavailable Cd in soil-water extracts (BSWE) and bioavailable Cd in soil-water suspensions (BSWS) were measured by the E. coli cadAp::luc-based whole-cell sensor. Final results showed that spiked SS (Si : Cd = 2 : 1, mol mol(-1)) reduced the different forms of Cd (TSWE, BSWE and BSWS) from 56.47 mg kg(-1), 42.11 mg kg(-1), and 206.72 mg kg(-1) to 16.63 mg kg(-1), 15.90 mg kg(-1), and 67.57 mg kg(-1), respectively. In other words, SS had 25.68%, 19.5%, and 9.54% better immobilizing efficiency, respectively, compared with DKP. All the results supported SS was more efficient than DKP at immobilizing Cd in soil, and higher soil pH and higher solubility of the immobilizing agents may have been the major factor affecting immobilizing efficiency. In addition, the total and bioavailable Cd in soil-water extracts was only 16.13-35.41% of the sensor contact assay-determined Cd (BSWS), which indicated that the whole-cell sensor-based contact assay was more practical in assessing the risk of Cd in soil after immobilization since it would not overrate the immobilizing capacity of the agents.


Assuntos
Cádmio/química , Escherichia coli/metabolismo , Fosfatos/química , Silicatos/química , Poluentes do Solo/química , Cádmio/metabolismo , Monitoramento Ambiental , Fosfatos/metabolismo , Silicatos/metabolismo , Solo/química , Poluentes do Solo/metabolismo
8.
Huan Jing Ke Xue ; 35(11): 4329-37, 2014 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-25639113

RESUMO

The dynamics of rhizospheric fungal diversity and biomass at different sampling stages associated with two transgenic insectresistant cottons expressing Cry1Ac protein and their control varieties were studied under greenhouse conditions, followed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time polymerase chain reaction (Q-PCR), in order to evaluate the ecological security of planting transgenic cotton expressing Cry1Ac protein. The results indicated that the fungal superior bands in rhizosphere of transgenic Bt cotton were similar with that of control cotton at four sampling stages, the more obvious difference in the blurred bands among transgenic Bt cotton, JM20 and SHIYUAN321 was detected. The rhizospheric fungal biomass of transgenic Bt cotton SGK321 was significantly lower than that of its parental control cotton at seedling stage, while the slight decrease in fungal biomass of transgenic Bt cotton XP188 was detected at boll forming stage, the ill-defined decrease, even growing tendency in two transgenic Bt cottons was detected at other stages. However, the difference of rhizospheric fungal community compositions and biomass was not only existed between transgenic cotton and its control, but also between SHIYUAN321 and JM20, and the same phenomenon was also detected between transgenic Bt cotton SGK321 and XP188. Hence, Bt protein is not the only incentive resulting in the difference in fungal community composition and diversity, the decrease in biomass between transgenic cotton and untransgenic cotton, different cotton varieties has an effect on them.


Assuntos
Fungos/classificação , Gossypium/microbiologia , Plantas Geneticamente Modificadas/microbiologia , Rizosfera , Animais , Proteínas de Bactérias/genética , Endotoxinas/genética , Gossypium/genética , Proteínas Hemolisinas/genética
9.
Huan Jing Ke Xue ; 34(4): 1448-56, 2013 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-23798128

RESUMO

Nitritation is an important part of the biological nitrogen removal process, and the performance of the process was determined by the microbial community structure. To explore the microbial adaptability to different sewage, the microbial diversity and the amount of bacteria were investigated in a high ammonia wastewater treatment process and a sewage treatment process using the clone library of bacterial 16S rDNA, the phospholipid fatty acid method (PLFA) and the quantitative PCR. The clone library results showed that there was a significantly difference in bacterial community structure of these two processes, although the dominant bacteria belong to the Proteobacteria and Bacteroidete, there were more clusters in the sewage treatment process. The PLFAs results showed that the microbial diversity index and the evenness index of the high ammonium wastewater treatment process were significantly low. The quantitative PCR results showed that amounts of ammonia oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the high ammonium wastewater treatment process were higher than these in sewage treatment process. The copy number of AOB was higher than the copy number of NOB in the high ammonia wastewater treatment process by three orders magnitude. The copy number of AOB was higher than the copy number of NOB in sewage treatment process by two orders of magnitude.


Assuntos
Bactérias/isolamento & purificação , Nitrificação , Compostos de Amônio Quaternário/análise , Esgotos/microbiologia , Águas Residuárias/microbiologia , Bacteroidetes/isolamento & purificação , Cidades , DNA Bacteriano/genética , Reação em Cadeia da Polimerase , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química
10.
Huan Jing Ke Xue ; 34(3): 1181-9, 2013 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-23745432

RESUMO

A microbial whole-cell biosensor CB10 for the bioavailability assessing of Cr6+ was constructed by molecular biotechnology. The regulatory gene and promoter of CB10 was from the chromium resistance system of plasmid pMOL28 from Cupriavidus metallidurans CH34, and the reporter gene of CB10 was luc which was derived from Photinus pyralis. Finally, its response characteristic was discussed under different incubation conditions e. g. pH and temperature. The results showed that a microbial whole-cell biosensor CB10 had been successfully constructed which could respond to Cr6+ within 30 min, with a LOD for Cr6+ of 2 micromol x L(-1). When the incubation concentration of Cr6+ was between 20 micromol x L(-1) and 200 micromol x L(-1), the luc activity of the CB10 biosensor was in linear correlation with the concentration of Cr6+. When the concentration of heavy metal was in the range of 10-50 micromol x L(-1), the response of CB10 was relatively more specific. Moreover, high concentrations of Pb2+, Mn2+ and Sb2+ could also induce CB10. By analyzing the response characteristic of CB10 biosensor, we could draw the conclusion that 15-30 degrees C and pH 4-7 were appropriate for CB10, and 30 degrees C and pH 7 were the optimal conditions for the incubation of the CB10 biosensor. The microbial whole-cell biosensor CB10 for the detection of Cr6+ was fast-responding, specific, sensitive and stable under various conditions. In prospective, it could be used in the fast detection of Cr6+ in water and assessment of the bioavailability of Cr6+ in soil.


Assuntos
Técnicas Biossensoriais/métodos , Cromo/análise , Cupriavidus/metabolismo , Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Animais , Disponibilidade Biológica , Cupriavidus/genética , Vaga-Lumes/genética
11.
Huan Jing Ke Xue ; 34(2): 760-6, 2013 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-23668152

RESUMO

A whole cell sensor, Pseudomonas fluorescens A506 (pTS), was immobilized by sodium alginate and the factors of cell density, immobilization time and beads usage were optimized. The performance of the immobilized cells was compared with that of the free cells. After 2 h immobilization,the increasing speed of fluorescent signal of immobilized cells was 2.26 times as high as that of the free cells,and the peak value was 2.23 times as high during the detection time ranging from 1.5 to 6.0 h. The constantly lower growth and density of the immobilized cell implied the enhanced signal intensity of single cells after immobilization. Meanwhile, the cell density decreased as the immobilization time prolonged. Cell density and immobilization time were the dominant factors affecting the detection signal. For benzene at higher concentrations, the immobilized biosensor showed more rapid signal response at the early period of detection.


Assuntos
Derivados de Benzeno/análise , Técnicas Biossensoriais/métodos , Poluentes Ambientais/análise , Pseudomonas fluorescens/citologia , Alginatos/química , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microbiologia Industrial/métodos , Pseudomonas fluorescens/metabolismo
12.
Huan Jing Ke Xue ; 34(1): 347-56, 2013 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-23487961

RESUMO

Microbial whole-cell biosensor is an excellent tool to assess the bioavailability of heavy metal in soil and water. However, the traditional physicochemical instruments are applied to detect the total metal. Furthermore, microbial whole-cell biosensor is simple, rapid and economical in manipulating, and is thus a highly qualified candidate for emergency detection of pollution incidents. The biological component of microbial whole-cell biosensor mostly consists of metalloregulatory proteins and reporter genes. In detail, metalloregulatory proteins mainly include the MerR family, ArsR family and RS family, and reporter genes mainly include gfp, lux and luc. Metalloregulatory protein and reporter gene are related to the sensitivity, specificity and properties in monitoring. The bioavailability of heavy metals is alterable under different conditions, influenced by pH, chelate and detection methods and so on. Increasing the accumulation of intracellular heavy metal, modifying the metalloregulatory proteins and optimizing the detecting conditions are important for improving the sensitivity, specificity and accuracy of the microbial whole-cell biosensor. The future direction of microbial whole-cell biosensor is to realize the monitoring of pollutions in situ and on line.


Assuntos
Bactérias/genética , Técnicas Biossensoriais/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Metais Pesados/análise , Bactérias/metabolismo , Biodegradação Ambiental , Disponibilidade Biológica , Poluentes Ambientais/metabolismo , Metais Pesados/metabolismo
13.
Ultrason Sonochem ; 20(1): 118-24, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22682477

RESUMO

An efficient intermittent ultrasonic treatment strategy was developed to improve laccase production from Trametes versicolor mycelia cultures. The optimized strategy consisted of exposing 2-day-old mycelia cultures to 5-min ultrasonic treatments for two times with a 12-h interval at the fixed ultrasonic power and frequency (120 W, 40 kHz). After 5 days of culture, this strategy produced the highest extracellular laccase activity of 588.9 U/L among all treatments tested which was 1.8-fold greater than the control without ultrasound treatment. The ultrasonic treatment resulted in a higher pellet porosity that facilitated the mass transfer of nutrients and metabolites from the pellets to the surrounding liquid. Furthermore, the ultrasonic treatment induced the expression of the laccase gene (lcc), which correlated with a sharp increase in both extracellular and intracellular laccase activity. This is the first study to find positive effects of ultrasound on gene expression in fungal cells. These results provide a basis for understanding the stimulation of metabolite production and process intensification by ultrasonic treatment in filamentous fungal culture.


Assuntos
Técnicas de Cultura/métodos , Lacase/biossíntese , Micélio/crescimento & desenvolvimento , Trametes/crescimento & desenvolvimento , Trametes/metabolismo , Ultrassom , Espaço Extracelular/enzimologia , Imersão , Espaço Intracelular/enzimologia , Lacase/genética , Micélio/citologia , Micélio/genética , Micélio/metabolismo , Trametes/citologia , Trametes/genética
14.
Huan Jing Ke Xue ; 33(1): 305-13, 2012 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-22452227

RESUMO

Microbial communities of different depths (30, 60, 100, 150, 200cm) from the unexploited oilfield, gas field and control area were studied by PCR-DGGE and sequencing methods. The objectives of this study were to understand the microbial distribution in the regions of unexploited oil and gas fields, and to investigate the potential microbial indicators of oil and gas resources. The results showed that the Dice coefficients between different depths were very low (26-69.9). The microbial communities in the soil of 150 cm and 200 cm depth had greater richness (S > or = 19), diversity (H > or = 2.69) and evenness (E > or = 0. 90). The results of sequencing demonstrated that the bands from oilfield were mainly grouped into alpha-Proteobacteria, gamma-Proteobacteria, Actinobacteria, Acidobacteria with the predominance of gamma-Proteobacteria (75%). Most of the bands were related to oil-associated and hydrocarbon degrading bacteria, such as Methylophaga and Alcanivorax. While the gas field had alpha, beta, gamma, delta-Proteobacteria and Bacteroidetes, and gamma-Proteobacteria accounted for only 24%. More strains showed relativity to methanotrophs, such as Methylocystaceae. Thus, 150 cm and 200 cm were more suitable as the oil-gas exploration sampling depth. Methylocystaceae may act as potential indicators for gas resources, Methylophaga and Alcanivorax for oil.


Assuntos
Bactérias/classificação , Campos de Petróleo e Gás/microbiologia , Microbiologia do Solo , Alcanivoraceae/genética , Alcanivoraceae/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , DNA Bacteriano/análise , DNA Bacteriano/isolamento & purificação , Eletroforese em Gel de Gradiente Desnaturante/métodos , Methylocystaceae/genética , Methylocystaceae/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/isolamento & purificação
15.
Bioresour Technol ; 102(17): 8099-104, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21737262

RESUMO

A newly isolated thermotolerant ethanologenic yeast strain, Issatchenkia orientalis IPE 100, was able to produce ethanol with a theoretical yield of 85% per g of glucose at 42°C. Ethanol production was inhibited by furfural, hydroxymethylfurfural and vanillin concentrations above 5.56 gL(-1), 7.81 gL(-1), and 3.17 gL(-1), respectively, but the strain was able to produce ethanol from enzymatically hydrolyzed steam-exploded cornstalk with 93.8% of theoretical yield and 0.91 gL(-1)h(-1) of productivity at 42°C. Therefore, I. orientalis IPE 100 is a potential candidate for commercial lignocelluloses-to-ethanol production.


Assuntos
Etanol/metabolismo , Fermentação , Lignina/antagonistas & inibidores , Leveduras/efeitos dos fármacos , Adaptação Fisiológica , Sequência de Bases , Reatores Biológicos , Primers do DNA , Hidrólise , Reação em Cadeia da Polimerase , Temperatura Ambiente , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo , Leveduras/fisiologia
16.
Huan Jing Ke Xue ; 30(5): 1292-7, 2009 May 15.
Artigo em Chinês | MEDLINE | ID: mdl-19558092

RESUMO

The indigenous microbial communities within the plant phyllosphere are highly diverse and include many different species of bacteria, filamentous fungi, yeasts and algae which play important ecological roles. This study was the first attempt to assess the impact of abamectin treatments on microbial communities of broccoli phyllosphere using two culture-independent techniques of phospholipid fatty acid analysis (PLFA) and terminal restriction fragment length polymorphism (T-RFLP). Results showed that low concentration of abamectin treatments did not affect the microbial biomass and microbial community structure of broccoli phyllosphere significantly. However, high concentration of abamectin treatments significantly change the microbial community structure including a decrease of total and bacterial biomass, and a decrease in the ratio of Gram-positive bacteria to Gram-negative bacteria, but did not change the fungal biomass. Moreover, PLFA suggested that the number of unsaturated and cyclopropane phospholipid fatty acids (PLFAs: 16: 1omega9t, 18: 1omega7, cy17:0 and cy19:0) increased with high concentration abamectin treatment, while the saturated PLFAs i15:0, a15:0, i16:0 and a17:0 decreased. The appearance terminal restriction fragments (T-RFs: 58, 96, 236 and 420 bp) indicated that some bacteria might play a significant role in abamectin degradation in broccoli phylosphere, while the disappeared T-RFs (51, 89, 99, 338, 66, 223 and 482 bp) implied some other bacteria might potentially serve as microbial indicator of abamectin exposure.


Assuntos
Bactérias/efeitos dos fármacos , Brassica/microbiologia , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Bactérias/classificação , Bactérias/genética , Biodiversidade , Ácidos Graxos/análise , Ivermectina/toxicidade , Fosfolipídeos/análise , Polimorfismo de Fragmento de Restrição
17.
Huan Jing Ke Xue ; 29(1): 225-30, 2008 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-18441945

RESUMO

A newly isolated Bacillus cereus strain HQ-1 was found to possess high capability to absorb silver ions. The study showed that the biosorption process could be described well by pseudo-second-order kinetic model and Freundlich isotherm model. Higher cell concentration was favorable to the biosorption. Temperature's effect on the biosorption was not obvious. The oxygenous and nitrogenous functional groups on the cell wall played a very important role in the process of biosorption. Microdeposits were formed by interaction between silver ions and biopolymers from the cell wall (such as polysaccharides, proteins and some hydrolysis).


Assuntos
Bacillus cereus/metabolismo , Eliminação de Resíduos/métodos , Prata/metabolismo , Bacillus cereus/efeitos dos fármacos , Bacillus cereus/ultraestrutura , Biodegradação Ambiental , Transporte Biológico , Farmacorresistência Bacteriana , Resíduos Industriais/análise , Metais Pesados/metabolismo , Metais Pesados/farmacocinética , Metais Pesados/farmacologia , Microscopia Eletrônica de Varredura , Prata/farmacocinética , Prata/farmacologia
18.
J Environ Sci (China) ; 19(9): 1114-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17966518

RESUMO

This study focused on the screening of cadmium-resistant bacterial strains from Pb-Zn tailing. We investigated the diversity of microbial community inhabiting Dong-san-cha Pb-Zn tailing in Beijing, China, by polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene of bacterial strain, and found two dominant strains in the DGGE profile. Using special culture media, we isolated two strong cadmium-resistant bacterial strains. On the basis of morphological, physiological, and biochemical characteristics, BIOLOG, and 16S rDNA sequencing, the two strains were identified as Bacillus cereus and Enterobacter cloacae. Minimal inhibitory concentrations (MICs) of heavy metals for the bacteria were determined. E. cloacae showed higher MIC values for heavy metals and a larger range of antibiotic resistance than B. cereus.


Assuntos
Bactérias/isolamento & purificação , Cádmio/farmacologia , Eletroforese em Gel de Poliacrilamida/métodos , Reação em Cadeia da Polimerase/métodos , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/ultraestrutura , Sequência de Bases , Primers do DNA , Resistência Microbiana a Medicamentos , Microscopia Eletrônica de Varredura
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