RESUMEN
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).
Asunto(s)
Bacillus cereus/metabolismo , Eliminación de Residuos/métodos , Plata/metabolismo , Bacillus cereus/efectos de los fármacos , Bacillus cereus/ultraestructura , Biodegradación Ambiental , Transporte Biológico , Farmacorresistencia Bacteriana , Residuos Industriales/análisis , Metales Pesados/metabolismo , Metales Pesados/farmacocinética , Metales Pesados/farmacología , Microscopía Electrónica de Rastreo , Plata/farmacocinética , Plata/farmacologíaRESUMEN
Five samples of soil collected from a lead and zinc mine were used to assess the effect of combined contamination of heavy metals on soil bacterial communities using a polyphasic approach including characterization of isolates by culture method, community level catabolic profiling in BIOLOG GN microplates, and genetic community fingerprinting by denaturing gradient gel electrophoresis of 16S rDNA fragments amplified by PCR from community DNA (PCR-DGGE). The structure of the bacterial community was affected to a certain extent by heavy metals. The PCR-DGGE analysis of 16S rRNA genes showed that there were significant differences in the structure of the microbial community among the soil samples, which were related to the contamination levels. The number of bacteria and the number of denaturing gradient gel electrophoresis (DGGE) bands in the soils increased with increasing distance from the lead and zinc mine tailing, whereas the concentration of lead (Pb) and cadmium (Cd) was decreased. Heavily polluted soils could be characterized by a community that differs from those of lightly polluted soils in richness and structure of dominating bacterial populations. The clustering analysis of the DGGE profiles showed that the bacteria in all the five samples of soil belonged to three clusters. The data from the BIOLOG analysis also showed the same result. This study showed that heavy metal contamination decreased both the biomass and diversity of the bacterial community in soil.
Asunto(s)
Plomo , Minería , Microbiología del Suelo , Contaminantes del Suelo , Zinc , Secuencia de Bases , Cartilla de ADN , Electroforesis en Gel de Poliacrilamida , Plomo/análisis , Contaminantes del Suelo/análisis , Espectrofotometría Atómica , Zinc/análisisRESUMEN
Fluorescence in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes was applied for analyzing the structure of sulfate reducing prokaryotes (SRPs) community in injection water of Shengli Oil Field. Eight probes and their various combinations were used to detect SRPs in the water. Results showed SRPs detected in the water were diverse, which followed in 4 bacterial phyla and 1 archaeal phylum. Total amount of SRPs was 2.86 x 10(4) cells/mL, accounting for 20% of total cells of microorganisms in the water of the Oil Field. Desulfovibrio and Desulfotomaculum cells were about 8.71% (+/- 4.45%) and 12.15% (+/- 3.90%) of the total microbial cells respectively, being dominant in the water. The relative amounts of SRPs belonging to Desulfobacterales and Syntrophobacterales, Thermodesulfobacteriales, and Thermodesulfovibro to total microbial cells in the water were 7.59% (+/- 2.92%), 3.57% (+/- 1.39%) and 2.32% (+/- 0.80%) respectively. In addition, SRPs belonging to Archaeoglobus were also detected with the amount of 4.29% (+/- 1.75%) of total microbial cells, which tells that archeal SRPs are also very important sulfate reducing microorganisms in the injection water of oil field.