两株降油菌株的分离及其降油特性

从华庆石油污染的土壤中筛选出2株能够对原油进行高效降解的微生物菌株A1和A2。通过菌种降解特性的单因素实验可得菌种生长和降解的优化条件为:温度28℃、pH=8.0、盐度2g/L条件下,A1和A2菌株的石油降解率均达到95%以上。

高效石油降解菌的筛选及石油污染土壤生物修复特性的研究

从陕北石油污染土壤中富集分离、优选出7株菌株,并进一步研究了7株菌的生理生化特性.菌株鉴定结果表明,SY21为不动细菌属,SY22为奈瑟氏球菌属,SY23为邻单胞菌属、SY24为黄单胞菌属、SY42为动胶菌属、SY43为黄杆菌属、SY44为假单胞菌属.7株菌的降油试验结果表明,降解8d后,加菌试样的石油烃降解率均达到80%左右,7株菌的石油烃降解速率高于目前已有的报道.接种量越大,石油菌数量越多,石油烃降解率随接种量的增加而提高.采用SY43和SY23菌株对土壤进行生物修复,试验结果表明,投加高效菌株SY43和SY23均可在较短的时间内将土壤中的石油污染物去除,去除率可达88.4%和73.4%,其中菌株SY43的修复效果优于SY23.

含油废水处理中石油降解菌的筛选及其降解条件优化

为筛选出高效含油废水降油菌,更好地利用生化法治理含油废水,从咸阳市中国石油长庆石化公司污水处理站采取水样,经过菌种的驯化、分离纯化得到17株石油降解菌,其中细菌13株,其余为放线菌或霉菌.经过30℃、180±2r/min恒温摇床振荡培养7d后筛选出2株优势石油降解菌:GA-4菌为芽孢杆菌属(Bacillus sp.)、GA-6菌为不动杆菌属(Acinetobacter sp.).在油浓度为2g/L时降油效果最好,GA-4菌与GA-6菌的降油率分别为41.18%,34.82%.GA-4菌与GA-6菌的最优降解条件分别为:30℃,pH为8.0,接种量为5%;28℃,pH为7.5,接种量为5%.

石油降解菌对石油烃中不同组分的降解及演化特征研究

从甘肃华庆油田油井附近石油污染的土壤中得到5种菌属的石油降解菌,以各菌剂对原油不同组分的降解率及其标志物演化参数为基础,利用GC-MS联用技术分析测定了7 d和15 d石油烃中正构烷烃、藿烷、芳香烃的降解率,用各种标志物反映各菌剂对原油中正构烷烃、藿烷、芳香烃演化特征.结果表明:F2、A5、混合菌(H)对于高碳数段的正构烷烃降解率高达60%以上,混合菌剂对于正构烷烃的降解较均衡;正构烷烃在前后两个阶段的降解呈现出对低碳和高碳降解的互补规律,奇偶碳数优势(OEP)在15 d更明显;F2菌剂的w(∑C21-)/w(∑C22+)值说明对其高碳数降解优势最明显;各菌w(Pr)/w(Ph)比值均大于原油,说明原油中类异戊二烯烷烃在不同菌剂的作用中发生了明显的降解.各菌剂作用能促使五环三萜类化合物的手性碳R构型向更稳定的S构型转化,短期内已接近转化终点;A5对藿烷降解的w(Ts)/w(Tm)比值最大(0.966),转化最彻底;A5、D4和F2菌株后期作用原油时,藿烷系列的降解速率明显大于正构烷烃系列,表现出降解藿烷的优势;各菌剂对芳香烃具有强烈的去甲基化作用,A5和D4菌降解芳烃优势更明显.

沙蚕对翅碱蓬-降油细菌系统降解菲效果的影响

选取近岸大型优势底栖动物多毛类双齿围沙蚕(Perinereis aibuhitensis)以及盐沼先锋植物翅碱蓬(Suaeda heteroptera),应用微宇宙方法比较沙蚕、翅碱蓬、降油细菌3种生物类型不同修复组合对菲的降解效果,分析不同修复组合对沉积质细菌数量的影响,揭示沙蚕对翅碱蓬-降油菌去除、降解菲的强化效应.结果表明,不同生物组合对土壤菲的降解率存在明显差异,降解率从高到低依次为沙蚕-翅碱蓬-降油菌>翅碱蓬-降油菌>沙蚕.其中,至实验30 d时,沙蚕-翅碱蓬-降油菌和翅碱蓬-降油菌两种生物组合对菲的总降解率分别达到97.02%和93.93%;不同生物组合平均降解率均随着时间的延长出现下降趋势;沙蚕对菲去除途径(翅碱蓬-降油菌交互作用、非生物因素)有显著的强化作用,最高强化贡献率分别达到14.32%、20.08%.在0-5 d沙蚕-翅碱蓬-降油菌组合中土壤降油菌数量显著高于翅碱蓬-降油菌组合;随着时间延长,两种生物组合降油菌数量均出现下降趋势,至实验20-30 d时均降至对照组水平.综上可知,沙蚕-翅碱蓬-降油菌联合修复模式较其它模式修复效果更显著,沙蚕对各去除因子降解以菲为代表的多环芳烃(PAHs)有明显的强化作用,并对降油菌生长有促进效果.

Antarctic Psychrophile Bacteria Screening for Oil Degradation and Their Degrading Characteristics

Two hydrocarbon degrading bacteria NJ276 and NJ341 were screened from 385 Antarctic marine bacteria and their degrading characteristics were studied. Diesel oil as sole carbon source was used in this study. The results showed that the oil degradation rates of Antarctic psychrophile bacteria NJ276 and NJ341 were 23.47 % and 32.15 %, respectively, after 20 days culturation at 5 ℃, and the rates were 43.95 % and 62.47 % respectively after 20 days culturation at 15 ℃. The oil degradation abilities were enhanced remarkably with the increasing culture temperature. GC - MSs indicated the residual oil contained C15 - C21 7 alkyls after degradation by NJ276, and C16, C17 and C18 3 alkyls after degradation by NJ341. The 16S rDNA gene sequences homology and phylogenetic analysis of the two Antarctic psychrophile bacteria showed that NJ276 belonged to the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia.

Biological Characteristics of Biosurfactantproducing Petroleum-degrader Bacterium Bacillus BS-8

The growth characteristics of petroleum-degrader BS-8（Bacillus sp.） and the factors influencing its biosurfactant production were tested; the biosurfactant releasing mode of BS-8 was speculated by measuring OD600, surface tension and oil displacement of fermentation broth; and the effects of carbon source, nitrogen source, temperature, p H, and Na Cl concentration on biosurfactant production by BS-8 were observed in this study. The results showed that the biosurfactant releasing mode of BS-8 was growth-correlated, the surface tension of BS-8 fermentation broth declined with the total bacteria increasing, and the oil displacement was positive correlated with biosurfactant content in fermentation broth; and the optimal culture conditions for effective biosurfactant production included： glucose as carbon source,yeast extract as nitrogen source, Na Cl concentration of 2%, p H of 7.0 and temperature at 30 ℃.

Response of Microbial Community to Petroleum Stress and Phosphate Dosage in Sediments of Jiaozhou Bay, China

The dynamic microcosms were used to evaluate the effect of oil spills on microbial ecological system in marine sediment and the enhancement of nutrient on the oil removal. The function and structure of microbial community caused by the oil pollution and phosphate dosage were simultaneously monitored by dehydrogenase activity assay and PCR-denaturing gradient gel electrophoresis(DGGE) techniques. The results indicated that the amount of total bacteria in all dynamic microcosms declined rapidly with incubation time. The number of petroleum-degrading bacteria and the activity of sediment dehydrogenase were gradually enhanced by petroleum in the oil-treated microcosms, while they both showed no obvious response to phosphate dosage. In comparison, phosphate spiked heterotrophic bacteria and they showed a significant increase in amount. DGGE profiles indicated that petroleum dosage greatly changed community structure, and the bacteria belonged to class Deltaproteobacteria, and phyla Bacteroidetes and Chlorobi were enriched. This study demonstrated that petroleum input greatly impacted the microbial community structure and consequently the marine sediment petroleum-degrading activity was enhanced. Phosphate dosage would multiply heterotrophic bacteria but not significantly enhance the petroleum degradation.

Isolation and Characterization of a Thermophilic Oil-Degrading Bacterial Consortium

In this study, a thermophilic oil-degrading bacterial consortium KO8-2 growing within the temperature range of 45--65℃ （with 55℃ being the optimum temperature） was isolated from oil-contaminated soil of Karamay in Xinjiang, China. Denaturing gradient gel electrophoresis （DGGE） showed that there were nine strains included in KO8-2, which originated from the genera of Bacillus, Geobacillus and Clostridium. They all belonged to thermophilic bacteria, and had been previously proved as degraders of at least one petroleum fraction. The crude oil degraded by KO8-2 was analyzed by infrared spectrophotometry, hydrocarbon group type analysis and gas chromatography. The results indicated that the bacterial consortium KO8-2 was able to utilize 64.33% of saturates, 27.06% of aromatics, 13.24% of resins and the oil removal efficiency reached up to 58.73% at 55 ~C when the oil concentration was 10 g/L. Detailed analysis showed that KO8-2 was able to utilize the hydrocarbon components before C19, and the n-alkanes ranging from C20--C33 were signifi- cantly degraded. The ratios of nC17/Pr and nC18/Ph were 3.12 and 3.87, respectively, before degradation, whereas after degradation the ratios reduced to 0.21 and 0.38, respectively. Compared with the control sample, the oil removal efficiency in KO8-2 composting reactor reached 50.12% after a degradation duration of 60 days.

Degradation Characteristics and Community Structure of a Hydrocarbon Degrading Bacterial Consortium

A hydrocarbon degrading bacterial consortium KO5-2 was isolated from oil-contaminated soil of Karamay in Xinjiang, China, which could remove 56.9% of 10 g/L total petroleum hydrocarbons(TPH) at 30 ℃ after 7 days of incubation, and could also remove 100% of fluorene, 98.93% of phenanthrene and 65.73% of pyrene within 3, 7 and 9 days, respectively. Twelve strains from six different genera were isolated from KO5-2 and only eight ones were able to utilize the TPH. The denaturing gradient gel electrophoresis(DGGE) was used to investigate the microbial community shifts in five different carbon sources(including TPH, saturated hydrocarbons, fluorene, phenanthrene and pyrene). The test results indicated that the community compositions of KO5-2 in carbon sources of TPH and saturated hydrocarbons, respectively, were roughly the same, while they were distinctive in the three different carbon sources of PAHs. Rhodococcus sp. and Pseudomonas sp. could survive in the five kinds of carbon sources. Bacillus sp., Sphingomonas sp. and Ochrobactrum sp. likely played key roles in the degradation of saturated hydrocarbons, PAHs and phenanthrene, respectively. This study showed that specific bacterial phylotypes were associated with different contaminants and complex interactions between bacterial species, and the medium conditions influenced the biodegradation capacity of the microbial communities involved in bioremediation processes.

Study on Isolation, Identification of A Petroleum Hydrocarbon Degrading Bacterium Bacillus fusiformis sp. and Influence of Environmental Factors on Degradation Efficiency

A hydrocarbon degrading bacterium KL2-13 was isolated from ten sites of oil contaminated soil in the Karamay oilfield. It was identified as the Bacillusfusiformis sp. bacterium based on its morphological and physiological characteristics and the 16S rDNA sequence analysis. The factors influencing the hydrocarbon degradation by the bacterium KL2-13 were determined. The test results have showed that the hydrocarbon degrading bacterium KL2-13 requires an optimum pH range of 6-8, and the optimum inoculation quantity is 3%. The low-concentration metal ions Fe^2＋, Mg^2＋ and Ca^2＋can improve the degradation ability of the bacteria KL2-13. A too low concentration of Tween-80 does not show obvious promotion to the degrading bacterium KL2-13, and an excessively high concentration can decrease the degradation ability of the bacterium, the best dosage of which is 2%. The hydrocarbon degrading rate reached 59.07%4-0.37% under the optimum culture conditions.

Development and characterization of a functional microbial consortium for crude oil degradation

Crude oil-degrading microbial consortia were enriched from three oil-contaminated sites to achieve the efficient biodegradation of crude oil,especially its refractory residues.The gravimetric method was used to analyze the degradation efficiency of the enriched consortia and changes in the fractions of the crude oil.The effects of changes in environmental factors were also studied to determine the optimal oil-reducing conditions and assess the dominant bacteria of the mixed flora.Results show that all three consortia exhibit reliable crude oil-biodegradation abilities and that their mixture results in biodegradation rate are as high as(48.0±3.5)%over 30 d of incubation.The consortium mixture can degrade 11.1%of the refractory resins,79.7%of the saturated hydrocarbons,and 45.7%of the aromatics in crude oil.Neutral pH,an incubation temperature of 30℃,and low mineral salt concentrations(0.8%to 4.0%)are optimal for crude oil biodegradation.The dominant genera in the consortium mixture include Pseudomonas,Stenotrophomonas,Brucella,Serratia,Brevundimonas,and Achromobacter.The richness and diversity of the microbial community in the consortium remain stable during crude oil degradation.Therefore,microbial enrichment from multiple sources may be performed to construct a mixed consortium for crude oil pollution bioremediation.

Isolation and Characterization of Microorganisms for Degradation of Minimal Oils and Fats at Low Temperatures

The isolation of microorganisms for biodegradation of minimal fats and oils at low temperatures was reported. By using rapeseed oil as a sole carbon source, six strains were isolated from five kinds of oils/fats-contaminated wastewater, soil, and active sludge. Among them, two strains which show the highest oil removal ratios were identified as Pseudomonas pseudoalcaligenes and Pseudomonas mendocina, respectively. The experiments of orthogonal impact conditions show that the optimal oil degradation condition is at pH 8.0, 5 ℃ and 100 mg/L oil. Under this condition, the rapeseed oil degradation ratios of two strains after 24 hours amount to 92.6% and 92.0% respectively, whereas the removal ratios of lard decrease to 39.5% and 54.3%.

Biodegradation of Petroleum Hydrocarbon by Pseudomonas Aeruginosa

A bacterial strain of the genus Pseudomonas aeruginosa was inoculated into a hydrocarbon culture medium and incubated for a definite period of time. The ability of the bacterial strain to biodegrade a hydrocarbon, viz. n-hexadecane, was evaluated through determining the hexadecane concentration in the inoculated culture medium on a gas chromatograph (GC). The effect of pH value on the degrading ability of the bacterial isolate and the impact of temperature on microbial growth were also explored. Test results showed that Pseudomonas aeruginosa was markedly effective in biodegrading n-hexadecane. Furthermore, the ability of Pseudomonas aeruginosa to biodegrade n-hexadecane was different at various pH values. Pseudomonas aeruginosa provided excellent degrading ability at a pH value of 7.0. The microbial cells of Pseudomonas aeruginosa increased with an increasing incubation duration at temperatures ranging from 28 ℃ to 35 ℃, and an exponential phase of microbial growth was observed.

Novel method for separation and screening of lubricant-degrading microorganisms and bacterial biodegradation

With the rapid increase of lubricant consumption, oil contamination becomes more serious. Biotreatment is an important method to remove oil contamination with some advantages. In this study, acclimatized oil- contaminated soil and used lubricating oil were sampled to isolate lubricant-degrading strains by several methods. 51 isolates were obtained and 24-well plates were employed to assess bacterial potential in high- throughput screening. The method was noted for the prominence of oil-water two-phase system with saving chemicals, shortening cycles and lessening workloads. In order to decrease inaccuracy, subculture and resting cells were inoculated into mineral salt medium with 200 μ1 oil in well plates for the cultivation at 37 ℃ for 5 and 7 days, and the biodegradation potential was characterized by the changes of oil film and cell density. With appropriate evaluation by shaking flask tests, 5 isolates were retained for their potentials with the maxi- mum biodegradation from 1500 to 2200 mg· L-1 and identified as Acidovorax dtrulli, Pseudomonos balearica, Adnetobacterjohnsonii （two isolates with different biodegradation potentials） and Addovorax avenae using 16S rRNA sequencing analysis. Also, lipase activity was determined using indicator titration and p-nitrophenyl palmitate （p-NPP） methods. The results indicated that only p-NPP was successful to test lipase activity with the range of 1.93-6.29 mg· L-1 Although these five strains could degrade 1000 mg· L-1 lubricating oil in 158-168 h, there existed distinct difference in enzyme activity, which demonstrates that lipase activity could not be used as the criterion to evaluate microbial biodegradation potential for petroleum hydrocarbons.

Isolation and characterization of a crude oil degrading bacteria from formation water:comparative genomic analysis of environmental Ochrobactrum intermedium isolate versus clinical strains

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 ℃ and pH 5.5. We sequenced the genome and found a single chromosome of 4800175 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 LMG3301T） showed that genes involved in virulence, disease, defense, phages, prophages, transposable elements, plasmids, and antibiotic resistance are also present in strain 2745-2.

Feasibility of Tea Saponin-Enhanced Soil Washing in a Soybean Oil-Water Solvent System to Extract PAHs/Cd/Ni Efficiently from a Coking Plant Site

Mixed contaminated brownfield sites have brought serious risks to human health and environmental safety. With the purpose of removing polycyclic aromatic hydrocarbons （PAHs） and heavy metals from a coking plant site, an innovative technology for ex-situ washing was developed in the present work. The combination of 15.0 mLL-1 soybean oil and 7.5 g L-1 tea saponin proved an effective method to extract co-pollutants from soil. After two consecutive washing cycles, the efficiency rates of removal for 3-, 4-, 5（＋6）-ring, and total PAHs, Cd, and Ni were approximately 98.2%, 96.4%, 92.3%, 96.3%, 94.1%, and 89.4%, respectively. Meanwhile, as evaluated by Tenax extraction method and metal stability indices, the residual PAHs and heavy metals after consecutive washing mainly existed in the form with extremely low bioaccessibility in the soil. Thus, in the soil after two washing cycles, there appeared limited environmental transfer risk of co-pollutants. Moreover, a subsequent precipitation method with alkaline solution and PAH- degrading strain Sphingobium sp. PHE9 inoculation effectively removed 84.6%-100% of Cd, 82.5%-91.7% of Ni, and 92.6%-98.4% of PAHs from the first and second washing solvents. The recovered solvents also exhibited a high recycling effectiveness. Therefore, the combined cleanup strategy proposed in this study proved environmentally friendly, which also played a major role in risk assessment and marlagement in mixed polluted sites.