RESUMEN
Paenibacillus sp. strain A2 is a Gram-negative rod-shaped bacterium isolated from a mixture of formation water and petroleum in Daqing oilfield, China. This facultative aerobic bacterium was found to have a broad capacity for metabolizing hydrocarbon and organosulfur compounds, which are the main reasons for the interest in sequencing its genome. Here we describe the features of Paenibacillus sp. strain A2, together with the genome sequence and its annotation. The 7,650,246 bp long genome (1 chromosome but no plasmid) exhibits a G+C content of 54.2 % and contains 7575 protein-coding and 49 RNA genes, including 3 rRNA genes. One putative alkane monooxygenase, one putative alkanesulfonate monooxygenase, one putative alkanesulfonate transporter and four putative sulfate transporters were found in the draft genome.
RESUMEN
In this study, we isolated an environmental clone of Ochrobactrum intermedium, strain 2745-2, from the formation water of Changqing oilfield in Shanxi, China, which can degrade crude oil. Strain 2745-2 is aerobic and rod-shaped with optimum growth at 42 °C and pH 5.5. We sequenced the genome and found a single chromosome of 4 800 175 bp, with a G+C content of 57.63%. Sixty RNAs and 4737 protein-coding genes were identified: many of the genes are responsible for the degradation, emulsification, and metabolizing of crude oil. A comparative genomic analysis with related clinical strains (M86, 229E, and LMG3301(T)) showed that genes involved in virulence, disease, defense, phages, prophages, transposable elements, plasmids, and antibiotic resistance are also present in strain 2745-2.
Asunto(s)
Proteínas Bacterianas/genética , Ochrobactrum/genética , Ochrobactrum/aislamiento & purificación , Petróleo/microbiología , Microbiología del Agua , Ochrobactrum/clasificación , Especificidad de la EspecieRESUMEN
Enhanced oil recovery using indigenous microorganisms has been successfully applied in the petroleum industry, but the role of microorganisms remains poorly understood. Here, we investigated the relationship between microbial population dynamics and oil production performance during a water flooding process coupled with nutrient injection in a low-temperature petroleum reservoir. Samples were collected monthly over a two-year period. The microbial composition of samples was determined using 16S rRNA gene pyrosequencing and real-time quantitative polymerase chain reaction analyses. Our results indicated that the microbial community structure in each production well microhabitat was dramatically altered during flooding with eutrophic water. As well as an increase in the density of microorganisms, biosurfactant producers, such as Pseudomonas, Alcaligenes, Rhodococcus, and Rhizobium, were detected in abundance. Furthermore, the density of these microorganisms was closely related to the incremental oil production. Oil emulsification and changes in the fluid-production profile were also observed. In addition, we found that microbial community structure was strongly correlated with environmental factors, such as water content and total nitrogen. These results suggest that injected nutrients increase the abundance of microorganisms, particularly biosurfactant producers. These bacteria and their metabolic products subsequently emulsify oil and alter fluid-production profiles to enhance oil recovery.
Asunto(s)
Bacterias/metabolismo , Petróleo/metabolismo , Microbiología del Agua , Alcaligenes/clasificación , Alcaligenes/genética , Alcaligenes/metabolismo , Bacterias/clasificación , Bacterias/genética , Secuencia de Bases , China , Frío , Cartilla de ADN , ADN Bacteriano/genética , Emulsiones , Reacción en Cadena de la Polimerasa , Pseudomonas/clasificación , Pseudomonas/genética , Pseudomonas/metabolismo , ARN Ribosómico 16S/genética , Rhizobium/clasificación , Rhizobium/genética , Rhizobium/metabolismo , Rhodococcus/clasificación , Rhodococcus/genética , Rhodococcus/metabolismo , Especificidad de la Especie , Temperatura , Agua/químicaRESUMEN
Enterobacter cloacae strain JD, which produces water-insoluble biopolymers at optimal temperature of 30°C, and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at high temperatures by protoplast fusion. The obtained fusant strain ZR3 produced exopolysaccharides at up to 45°C with optimal growth temperature at 35°C. The fusant produced exopolysaccharides of approximately 7.5 g/L or more at pH between 7.0 and 9.0. The feasibility of the enhancement of crude oil recovery with the fusant was tested in a sand-packed column at 40°C. The results demonstrated that bioaugmentation of the fusant was promising approach for MEOR. Mass growth of the fusant was confirmed in fermentor tests.
Asunto(s)
Enterobacter cloacae/metabolismo , Ingeniería Genética , Geobacillus/metabolismo , Fusión de Membrana , Aceites/metabolismo , Polisacáridos Bacterianos/biosíntesis , Protoplastos/metabolismo , Biodegradación Ambiental , Reactores Biológicos/microbiología , Enterobacter cloacae/crecimiento & desarrollo , Geobacillus/crecimiento & desarrollo , Concentración de Iones de Hidrógeno , Dióxido de Silicio , AguaRESUMEN
The distribution of microbial communities in the Menggulin (MGL) and Ba19 blocks in the Huabei Oilfield, China, were studied based on 16S rRNA gene analysis. The dominant microbes showed obvious block-specific characteristics, and the two blocks had substantially different bacterial and archaeal communities. In the moderate-temperature MGL block, the bacteria were mainly Epsilonproteobacteria and Alphaproteobacteria, and the archaea were methanogens belonging to Methanolinea, Methanothermobacter, Methanosaeta, and Methanocella. However, in the high-temperature Ba19 block, the predominant bacteria were Gammaproteobacteria, and the predominant archaea were Methanothermobacter and Methanosaeta. In spite of shared taxa in the blocks, differences among wells in the same block were obvious, especially for bacterial communities in the MGL block. Compared to the bacterial communities, the archaeal communities were much more conserved within blocks and were not affected by the variation in the bacterial communities.
Asunto(s)
Archaea/crecimiento & desarrollo , Bacterias/crecimiento & desarrollo , Yacimiento de Petróleo y Gas/microbiología , Petróleo/microbiología , Temperatura , Microbiología del Agua , Archaea/clasificación , Archaea/genética , Bacterias/clasificación , Bacterias/genética , Secuencia de Bases , China , Análisis por Conglomerados , Biblioteca de Genes , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Factores de TiempoRESUMEN
A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant was composed of high percentage lipid (â¼74%, w/w) and carbohydrate (â¼20%, w/w) in addition to a minor fraction of protein (â¼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0-8.0. The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m and emulsified kerosene up to EI(24) ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil recovery efficiency of strain and its biosurfactant was 23.02% residual oil.