Growth factors, kinetics and biodegradation mechanism associated with Pseudomonas nitroreducens TX1 grown on octylphenol polyethoxylates

The growth properties and biodegradation mechanism of a Gram-negative bacterium, Pseudomonas nitroreducens TX1 that was able to grow on branched octylphenol polyethoxylates (OPEO(n), average n=9.5) as the sole carbon source over a wide concentration range (1-100,000 mgl(-1)) were studied. Analysis of growth factors indicated the highest specific growth rate (micro) of 0.53 h(-1) was obtained at an initial concentration of 5,000 mgl(-1) OPEO(n). An optimal C/N ratio of 12 was obtained for (NH(4))(2)SO(4) as the nitrogen source in a cultivated medium at pH 7. The kinetic analysis demonstrated that bacterial growth and OPEO(n) degradation followed the Monod equation and were based on a substrate concentration inhibition model and pseudo-first-order reaction, respectively. The substrate inhibition coefficient was over 18,000 mgl(-1) and this indicates that the strain has an ability to sustain growth at high concentrations of OPEO(n) and use it as the sole carbon source under such a stress condition. Furthermore, LC-MS analysis showed that the biodegradation mechanism of dodecyl octaethoxylate (AEO8) by P. nitroreducens TX1 was the sequential cleavage of the ethoxylate chain.     

蒽生物降解及其动力学分析

从长期被石油污染的土壤中分离了一株优势菌,经鉴定为铜绿假单胞菌,研究了该菌株对蒽的降解性能,结果发现该菌株对蒽有良好的降解效果。经过147h的降解,蒽的浓度从100mg/L降至27.5mg/L,降解了72.5mg/L,降解率达72.5%,显示了极强的降蒽能力。同时,进行了动力学分析,结果表明蒽的残留浓度Y(mg/L)与时间t(h)符合方程Y=90.4322e(-0.0098)x。     

Isolation, characterization and phylogenetic analysis of a bacterial strain capable of degrading acetamiprid

An aerobic bacterium, capable of degrading the new chloronicotine pesticide acetamiprid, was isolated from the sludge of pesticide factory after successive enrichment cultures and named strain FH2 which is a Gram-negative, rod-shaped, obligate aerobic org     

聚合物驱采出水中聚丙烯酰胺的微生物联合降解作用研究

通过对2株细菌的培养降解实验研究聚丙烯酰胺(hydrolyzed polyacrylamide,HPAM)降解菌对水环境下聚丙烯酰胺的降解作用,讨论协同降解机理。2株降解聚丙烯酰胺的菌株假单胞菌CJ419、枯草芽孢杆菌FA16在初始30℃废水样品上培养,定期测量细菌生物量和HPAM降解率。培养30 d后CJ419和FA16对聚合物的降解率最大值分别达到30.4%和25%,而以1∶1比例的混合菌降解率最大值达到80.3%。对2株菌胞外各组分研究表明:混合菌降解HPAM的机理主要由胞外降解酶系水解聚合物侧链基团导致HPAM降解为小分子物质,同时生长过程中降解菌还会释放非蛋白还原性物质引发氧化反应共同参与HPAM降解。     

恶臭假单胞菌降解苯酚的动力学研究

研究了恶臭假单胞菌（Pseudomonas putida LY1）利用苯酚作为唯一碳源和能源时的生长动力学特性。通过对该菌株在不同温度、pH和初始苯酚浓度下的生长和降解情况的研究,可知该菌株在温度为25℃左右、pH为中性和偏碱性的条件下具有更高的降解活性。细菌的生长动力学过程符合基质抑制型的Haldane方程,可利用该...     

Effects of methamidophos on the community structure,antagonism towards Rhizoctonia solani,and phlD diversity of soil Pseudomonas

A microcosm incubation study using an aquic brown soil from northeast China (a Cambisol in the UN Food and Agriculture Organization FAO Soil Taxonomy) was conducted to examine the effects of different concentrations (0, 50, 150, and 250 mg kg^?1) of methamidophos (O,S-dimethyl phosphoramidothioato) on Pseudomonas, one of the most important gram-negative bacteria in soil. Amplified ribosomal DNA restriction analysis (ARDRA) was performed to study the Pseudomonas community structure, an in vitro assay was made to test the antagonistic activity of isolated Pseudomonas strains against soil-borne Rhizoctonia solani, a major member of the pathogens highly related to soil-borne plant diseases, and special primer amplification and sequencing were performed to investigate the diversity of phlD, an essential gene in the biosynthesis of 2, 4-diacetylphloroglucinol (2, 4-DAPG), which has biocontrol activity in phlD ⁺isolates. With exposure to increasing methamidophos concentrations, the total number of soil Pseudomonas ARDRA patterns decreased significantly, but with less change in the same treatments over 1, 3, and 5 weeks of incubation. The number of isolated Pseudomonas strains with antagonistic activity against R. solani as well as the diversity and appearance frequency of the strains' phlD gene also decreased with increasing concentrations of methamidophos, especially at high methamidophos concentrations. Applying methamidophos could increase the risk of soil-borne plant diseases by decreasing the diversity of the soil Pseudomonas community and the amount of R. solani antagonists, particularly those with the phlD gene.     

嗜油菌NY3对蜡质油污泥无害化处理

蜡质油污泥(WOS)成分复杂,含大量老化原油、蜡质油、沥青质及其他化学药剂,属危险性固体废弃物,大量排放已成为石化企业可持续发展的障碍.研究利用铜绿假单胞菌NY3处理高浓度WOS的条件,结果表明,WOS∶木屑(m/m)(d =0.30 mm) 7∶1并结合热熔分散为最佳油污泥预处理条件;液相降解体系含油量为24.5 g/L时,6d内,油泥中C20以下的正构烷烃完全被去除,C21～C34和C35～C38大分子量正构烷烃去除率分别在91％ ～99％和78％ ～ 89％之间.添加鼠李糖脂能明显提高长链烃和多环芳烃的降解率.6d内210 mg/L鼠李糖脂使C29 ～ C38的降解率提高17.27％ ～36.65％,芘、菲分别提高13.67％和16.12％.添加葡萄糖和Fe2+的条件下,NY3菌可将油污泥转化成为糖蛋白,产量达28 g/L.     

Pseudomonas sp.fz胞外分离物降解四溴双酚A

四溴双酚A(TBBPA)是全球消耗量最大的溴系阻燃剂。通过活性物质的定位、分离和TBBPA产物的分析等步骤,对Pseudomonas sp.fz胞外分离物降解TBBPA进行了研究。结果表明,存在于胞外的活性物质通过异丙基断裂和脱溴两条途径降解TBBPA。通过超滤,Sephadex G-10分离纯化得到了具有降解活性的小分子物质,分子量约为376~456 Da,初步鉴定为短肽类物质。这种小分子物质具有很好的热稳定性(30~80℃),在弱酸性条件下(2.0~5.0)活性较高,其活性还受金属离子、氧气和抑制剂(Na N3)的影响。此外,部分纯化的小分子物质在一定条件下能够产生羟基自由基(·OH)。     

Bioremediation of kerosene I: A case study in liquid media

The ability of different local isolates in addition to some isolates from Germany to degrade kerosene in liquid medium was studied. The results showed that the percent of kerosene degradation varied among the different organisms and that 59–94% of kerosene was degraded after 21 d. Two local isolates (Pseudomonas sp. AP and Pseudomonas sp. CK) and one German isolate (Gordonia sp. DM) were selected for this study. The addition of wheat bran, as co-substrate, stimulated the kerosene degradation by the two local strains, while glucose inhibited the degradation rate using the three organisms with different rates. Ammonium nitrate and urea was the best nitrogen sources. The use of superphosphate (as phosphorus source) in the presence of urea stimulates the degradation rate. It was also observed that the addition of 1% surfactants, like Triton X-100, Igepal, Tergitol, or Tween 20 and 80 enhanced the kerosene degradation. The degradation percent lied between 94% and 98%. The ability of the tested organisms to degrade kerosene concentration from 2% to 8% was evaluated. It was found that the three organisms degraded about 65–85% from 8% kerosene after 21 d. The use of rice straw-immobilized cells reduced the time of degradation and enhanced the degradation ability of the organisms. The sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed the presence of a common protein band when the tested organisms were grown on kerosene.     

不同碳源和碳氮比对一株好氧反硝化细菌脱氮性能的影响

利用间歇培养装置研究了好氧条件下丁二酸盐、乙酸盐和苹果酸盐3种不同碳源对好氧反硝化细菌X31脱氮性能的影响,并就不同碳氮比(C/N)条件下菌株X31的反硝化能力展开了研究.结果显示,不同碳源种类对菌株硝酸还原酶活性有明显影响.以丁二酸盐和乙酸盐作为碳源时,其脱氮效果均要明显好于苹果酸盐作为碳源.以乙酸盐作为碳源时菌株的反硝化速率要稍高于丁二酸盐作为碳源,其反硝化速率可以达到11.86 mg·g-1·h-1.不同碳氮比(C/N)条件下,X31菌株的好氧反硝化能力亦不相同.当C/N大于5时,脱氮率能达到90%以上.最适宜的碳氮比是5～6,在此区间能进行完全的反硝化.当C/N在1～14之间变化时,硝酸盐还原基本都发生在菌株生长的第4～10 h,整个反硝化过程中亚硝酸盐浓度一直保持在极低的水平.