Biofilm comprising phototrophic, diazotrophic, and hydrocarbon-utilizing bacteria: a promising consortium in the bioremediation of aquatic hydrocarbon pollutants

Biofilms harboring simultaneously anoxygenic and oxygenic phototrophic bacteria, diazotrophic bacteria, and hydrocarbon-utilizing bacteria were established on glass slides suspended in pristine and oily seawater. Via denaturing gradient gel electrophoresis analysis on PCR-amplified rRNA gene sequence fragments from the extracted DNA from biofilms, followed by band amplification, biofilm composition was determined. The biofilms contained anoxygenic phototrophs belonging to alphaproteobacteria; pico- and filamentous cyanobacteria (oxygenic phototrophs); two species of the diazotroph Azospirillum; and two hydrocarbon-utilizing gammaproteobacterial genera, Cycloclasticus and Oleibacter. The coexistence of all these microbial taxa with different physiologies in the biofilm makes the whole community nutritionally self-sufficient and adequately aerated, a condition quite suitable for the microbial biodegradation of aquatic pollutant hydrocarbons.     

硫化物自养反硝化细菌颗粒污泥及其物化特征

采用上升流式缺氧颗粒污泥反应器成功驯化培养出了高性能的硫化物自养反硝化细菌颗粒污泥。反应器60 d完成污泥颗粒化,200 d后成熟的颗粒污泥平均粒径稳定在1 400 μm,SVI5和SVI30分别平均为（21.6±0.3）mL·g-1和（21.0±0.9）mL·g-1;系统稳定运行后,在污泥氮硫负荷分别为0.33 kg N·（m3·d）-1和0.62 kg S·（m3·d）-1,水力停留时间为5 h,脱氮效率保持在95%以上。与此同时,对接种污泥与颗粒污泥的物化特征进行对比分析发现,培养前后的污泥的无机组分与有机成分发生显著变化,Ca等元素参与并促进了颗粒污泥的形成,随着颗粒化的形成,蛋白质、多糖、脂质等物质均有不同程度的增长,使得颗粒污泥具有良好的脱氮性能,且结构和稳定性良好。     

微生物浸取废弃电路板粉末中的铜

以单质硫为能源物质,城市污水厂污泥为菌株来源及培养基主要成分来培养氧化硫硫杆菌.取100 mL氧化硫硫杆菌菌液用于浸取15 g废弃电路板粉末中的铜,反应到顶设时间后进行固液分离,另取100 mL氧化硫硫杆菌菌液用于继续浸取剩余固体中的铜,考察不同浸取频次对铜累计浸取率的影响.研究结果表明,随着浸取频次的增加,铜累计浸取率逐渐提高.耗时24 d,浸取频次分别为3、4、6、12、24次中.浸取24次的铜累计浸取率最高,为93.69%,其次是浸取12次的,铜累计浸取率为91.18%.虽然浸取24次的铜累计浸取率比浸取12次的高,但是前者在耗时24 d后产生的浸取液(2.4 L)是后者(1.2 L)的2倍,考虑到微生物培养及后续处理成本,所以最佳浸取频次为12次.     

Bioleaching of metal from municipal waste incineration fly ash using a mixed culture of sulfur-oxidizing and iron-oxidizing bacteria

We investigated the behavior and characteristics of metal leaching from municipal solid waste incineration (MSWI) fly ash among pure cultures of a sulfur-oxidizing bacterium (SOB) and an iron-oxidizing bacterium (IOB) and a mixed culture. The IOB has a high metal-leaching ability, though its tolerability against the ash addition is low. The SOB might better tolerate an increase in ash addition than the IOB, though metal leaching ability of the SOB is limited. Mixed culture could compensate for these deficiencies, and high metal leachability was exhibited in the 1% ash culture, i.e., 67% and 78% of leachabilities for Cu and Zn, respectively, and 100% for Cr and Cd. Furthermore, comparably high leachabilities such as 42% and 78% for Cu and Zn were observed even in the 3% ash cultures. Characterization of metal leaching by the mixed culture revealed that the acidic and oxidizing condition had remained stable thorough the experimental period. Ferric iron remained in the mixed culture, and the metal leaching was enhanced by redox mechanisms coupling with the leaching by sulfate. An increase of ferrous iron enhanced the Cr, Cu, and As leaching. The optimum concentration of sulfur existed for As and Cr (5 gl(-1)) and Cu (2 gl(-1)). The presence of the degradable and non-degradable organic compound that must be existed in the natural environment or waste landfills made no significant change in the leachability of metals other than Zn. These results suggested that bioleaching using a mixed culture of SOB and IOB is a promising technology for recovering the valuable metals from MSWI fly ash.     

Organochlorine residues in odontocete species from the southeast coast of India

Blubber from bottle-nose dolphins, spinner dolphins, humpback dolphin (Tursiops truncatus, Stenella longirostris and Sousa chinensis) were collected from the Bay of Bengal (southeast coast of India) and analyzed for the organochlorine pesticides hexachlorocyclohexane (HCHs), p,p'-dichlorodiphenyl trichloroethane (DDTs), and polychlorinated biphenyls (PCBs). All nine specimens analyzed contained considerable levels of all the three chemical classes where DDT was in the range of 3330-23330 ng/g; HCHs in the range of 95-765 ng/g; and PCBs in the range of 210-1220 ng/g (wet weight basis). The reasons for this and the variations in the isomer pattern of HCHs and DDT and its metabolites in marine mammal tissues are discussed.     

Bioleaching of heavy metals from livestock sludge by indigenous sulfur-oxidizing bacteria: effects of sludge solids concentration

A technologically and economically feasible process called bioleaching was used for the removal of heavy metals from livestock sludge with indigenous sulfur-oxidizing bacteria in this study. The effects of sludge solids concentration on the bioleaching process were examined in a batch bioreactor. Due to the buffering capacity of sludge solids, the rates of pH reduction, ORP rise and metal solubilization were reduced with the increase of the solids concentration. No apparent influence of solids concentration on sulfate produced by sulfur-oxidizing bacteria was observed when the solids concentration was less than 4% (w/v). A Michaelis-Menten type of equation was able to well describe the relationship between solids concentration and rate of metal solubilization. Besides, high efficiencies of metal solubilization were achieved after 16 d of bioleaching. Therefore, the bioleaching process used in this study could be applied to remove heavy metals effectively from the livestock sludge.     

Butyltins in water, biofilm, animals and sediments of the west coast of India

Biofilm, fish, oyster, mussel, clam, surface seawater, suspended particulate matter (SPM), and sediment samples were collected from marine and/or estuarine waters of the west coast of India. These samples were analysed for butyltin derivatives such as dibutyltin (DBT) and tributyltin (TBT). The concentrations DBT plus TBT varied between 2.4 and 8.3, 163 and 363 ng/l, 5 and 2853 ng/g dry wt in the SPM, seawater and sediment samples, respectively, of the Marmugao harbour. The values of DBT plus TBT ranged between 0.60 and 29, 123 and 242 ng/l and 1.4 and 65 ng/g dry wt in SPM, water and sediment samples, respectively, collected from the Mandovi estuary. In the Dona Paula Bay the DBT plus TBT varied from 10 to 89 ng/l in surface seawater, and TBT from 10 to 513 ng/g in biofilm samples. For the coastal sediment samples the concentration of DBT plus TBT ranged between 36 and 133 ng/g dry wt of sediment. For the animal samples the DBT plus TBT ranged between 58 and 825 ng/g dry wt of the tissue. Mussel tissues contained the highest amount of DBT plus TBT (825 ng/g dry wt tissue), whereas highest TBT concentration was recorded in the oyster (732 ng/g dry wt). TBT was generally the most abundant butyltin compound in most of the samples suggesting fresh inputs and/or less degradation of TBT. A wide range of the observed butyltin concentrations suggests the presence of localized areas of contamination. Leaching of tributyltin-containing antifouling paints from the ocean going ships, fishing and recreational boats, barges, and the inputs of TBT from the Goa shipyard and dry dock facility situated in the harbour are the probable sources of the DBT and TBT in the samples of the west coast of India. Higher levels of TBT were observed in biofilm relative to that in the surrounding seawater. When fed on TBT contaminated biofilm of the diatom Navicula subinflata, butyltin concentrations in the clam Paphia malabarica increased over the period of feeding suggesting the importance of biofilm in the transfer of butyltins to higher group of organisms.     

Assessment of acid leachable trace metals in sediment cores from River Uppanar, Cuddalore, Southeast coast of India

An acid leachable technique is employed in core samples (C1, C2 and C3) to develop a baseline data on the sediment quality for trace metals of River Uppanar, Cuddalore, southeast coast of India. Acid leachable metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn and Cd) indicate peak values at the sulphidic phase and enrichment of metals in the surface layers are due to the anthropogenic activities. Association of trace metals with Fe, Mn indicates their adsorption onto Fe-Mn oxyhydroxides and their correlation with S indicate that they are precipitated as metal sulphides. Factor analysis identified three possible types of geochemical associations and the supremacy of trace metals along with Fe, Mn, S and mud supports their geochemical associations. Factor analysis also signifies that anthropogenic activities have affected both the estuarine and fresh water regions of River Uppanar.     

Isolation of mesotrione-degrading bacteria from aquatic environments in Brazil

Mesotrione is a benzoylcyclohexane-1,3-dione herbicide that inhibits 4-hydroxyphenyl pyruvate dioxygenase in target plants. Although it has been used since 2000, only a limited number of degrading microorganisms have been reported. Mesotrione-degrading bacteria were selected among strains isolated from Brazilian aquatic environments, located near corn fields treated with this herbicide. Pantoea ananatis was found to rapidly and completely degrade mesotrione. Mesotrione did not serve as a sole C, N, or S source for growth of P. ananatis, and mesotrione catabolism required glucose supplementation to minimal media. LC-MS/MS analyses indicated that mesotrione degradation produced intermediates other than 2-amino-4-methylsulfonyl benzoic acid or 4-methylsulfonyl-2-nitrobenzoic acid, two metabolites previously identified in a mesotrione-degrading Bacillus strain. Since P. ananatis rapidly degraded mesotrione, this strain might be useful for bioremediation purposes.     

固废拆解场污染土壤中多环芳烃降解菌的筛选鉴定与降解特性

以腐植酸(HA) 溶液为吸附剂、从受多环芳烃污染的土壤中分离出来的降解菌制成为生物修复剂,以多环芳烃(PAHs)萘、菲、芘、荧蒽、苯并蒽、苯并芘为土壤污染物,对PAHs污染土壤进行修复实验。目的是筛选与分离吸附于HA的PAHs降解菌,研究HA与降解菌的协同效应对PAHs的降解效率的影响。用经过HA吸附的PAHs富集分离培养出1株高效降解菌株, 命名为Tzyx3,鉴定其为解脂耶氏酵母菌(Yarrowia lipolytica)。15 d后,土壤中萘、菲、芘、荧蒽、苯并蒽、苯并芘的降解率分别为90.7%、91.0%、74.7%、86.9%、84.7%和74.7%,表明Tzyx3和HA在PAHs污染土壤中存在协作关系,Tzyx3能够直接利用HA对土壤中的多环芳烃进行降解。     

2株乙酰甲胺磷降解菌的分离鉴定及降解特性研究

利用富集及驯化培养方法,从长期生产农药企业的废水处理系统、厂房周边污染的土壤和池水中,分离筛选出2株能够高效降解乙酰甲胺磷的菌株Y3、Y6。在形态特征和生理生化鉴定的基础上,对其16S rDNA序列进行了分析,并重点研究了它们对乙酰甲胺磷及其他农药的降解特性和抗性。结果表明,Y3、Y6分别为寡养单胞菌(Stenotrophomonas)和假单胞菌(Pseudomonas)。Y3、Y6在乙酰甲胺磷浓度分别为500 mg/L和1 000 mg/L,培养温度30℃,初始pH8,接种量为2.5%条件下,一周内可以将80%左右的乙酰甲胺磷矿化为磷酸根。外加葡萄糖及酵母膏对降解效率的研究表明,当酵母膏含量为1 g/L时,降解效果最理想;而外加葡萄糖的量,能相对抑制其对农药的降解。抗性实验显示,Y3、Y6均可在较高浓度的其他有机磷类及氨基甲酸酯类农药的普通培养基中生长,对其他农药的抗性也比较广泛。植物侵染实验显示,Y3、Y6对实验中的豆科、禾本科、十字花科及葫芦科植物不具备致病性,说明Y3、Y6环境安全性较强。     

甲醛降解细菌的分离鉴定和降解效果测定

从某化工厂污水处理系统的活性污泥中分离纯化得到一株能降解甲醛的革兰氏阳性菌,对其进行形态及生理生化特性测定,提取并纯化其基因组DNA,通过PCR扩增菌株的16S rDNA,测序结果表明,该菌株和苏云金芽孢杆菌的同源性为100%。在含1.2 μL/mL的甲醛的培养基上培养该菌36 h后,甲醛降解去除率达到72％以上。     

一株鱼粉加工硫化氢恶臭气体脱除菌株的分离与鉴定

鱼粉是水产动物、及畜禽动物养殖饲料中无法替代的优质动物蛋白源。然而因加工原料新鲜度不断下降、腐败等原因,鱼粉加工过程中会释放出大量的硫化氢恶臭气体,导致周边环境的严重污染。取鱼粉厂污水沉淀池中的污泥,对脱硫微生物进行富集、分离、纯化、检测脱硫效率,得到一株高效脱硫菌株XJ-2,其脱硫效率达87.1%。通过菌株形态观察、生理生化实验、API 50CHB试剂条检测及16S rDNA测序鉴定,结果确定该菌为蜡状芽孢杆菌(Bacillus cereus)。研究菌株XJ-2生长特性,发现菌株对环境中的pH值耐受力较强,不耐高温,正好避开鱼粉厂休业期,且经生长曲线研究发现该菌的稳定期较长,具有良好的应用前景。此研究将为生物法脱除鱼粉加工恶臭气体的应用提供一定的理论基础。     

Isolation and characteristics of sulfentrazone-degrading bacteria

This study aimed to isolate and characterize bacteria able to use sulfentrazone in the commercial formulation as their sole carbon source. The isolation of the potential sulfentrazone-degrading bacteria was made from soil samples with a recent history of herbicide application and from isolates identified through rDNA sequencing. Subsequently, we assessed the growth of the isolates and their sulfentrazone degradation ability using high-performance liquid chromatography. Twenty-six potential sulfentrazone-degrading bacterial isolates were obtained in pure culture. Through analysis of the rDNA sequences, the predominance of bacterial species of the genus Pseudomonas was found. The isolates presented a differentiated ability of sulfentrazone degradation. The presence of herbicide in the culture medium reduced the log phase of four isolates. Pseudomonas putida, Pseudomonas lutea, Pseudomonas plecoglossicida and three isolates of Pseudomonas sp. showed higher sulfentrazone degradation capacity, which varied from 4 to 15%. This is the first report of the Pseudomonas genre capable of sulfentrazone degradation. The isolates obtained present potential use in bioremediation programs for soil contaminated with sulfentrazone.     

Soil microbial parameters and luminescent bacteria assays as indicators for in situ bioremediation of TNT-contaminated soils

In situ bioremediation is increasingly being discussed as a useful strategy for cleaning up contaminated soils. Compared to established ex situ procedures, meaningful and reliable approaches for monitoring the remediation processes and their efficiency are of special importance. The subject of this study was the significance of two bioassays for monitoring purposes. The work was performed within the scope of a research project on the in situ bioremediation of topsoil contaminated with 2,4,6-trinitrotoluene (TNT). To evaluate changes within different experimental fields during a 17-month remediation period, the results of soil microbial assays and luminescent bacteria assays were compared with chemical monitoring data. The luminescent bacteria assays showed a significant reduction of the water-soluble soil toxicants in the treated fields. This bioassay proved to be a sensitive screening indicator of toxicity and may effectively aid the ecotoxicological interpretation of chemical monitoring data. Microbial biomass (C(mic)), the metabolic quotient (qCO2), and the ratio of microbial to organic carbon (C(mic)/C(org)) showed a highly significant correlation with total concentrations of TNT in the soil. But, in contrast to luminescent bacteria assays, this approach did not reveal any recovery of the soil at the end of the remediation period. There is clear evidence for persistent adverse effects of chronic TNT contamination on the site-specific microbial community and the local carbon cycle in the soil. The study clearly exhibits the differences between, as well as the complementary value of both bioassay approaches for monitoring short-term and long-term effects of soil contamination and the efficiency of remediation.     

Petrosia testudinaria as a biomarker for metal contamination at Gulf of Mannar, southeast coast of India

Coastal marine ecosystems in many parts of the world are under unrelenting stress caused by urban development, pollutants and other ecological impacts such as building of infrastructure, land reclamation for port and industrial development, habitat modification, tourism and recreational activities. The present work is a first extensive field study using the marine sponge, Petrosia testudinaria as a biomarker to detect heavy metal pollution between near and off shore environment of 'Gulf of Mannar', India. Sponges were collected from near shore (0.5-1 km) and offshore (5-7 km), locations and their metal concentrations were determined by inductively coupled plasma-mass spectrometry (ICPMS). Our results show that the near shore sponge accumulated greater concentrations of heavy metals (Al, Fe, Mn, As, Ni, Co, Cu, Se) ranging from 0.13 to 64 times higher concentration than the sponges located away from the shore. The results indicate that the accumulated metals alter the macromolecule composition (sugars, proteins and lipids) in near shore sponges. Frequent monitoring is necessary to assess the eco-health of the marine environment by choosing bioindicator species like sponges, which provide accurate, reliable measurement of environmental quality.     

Seasonal variation of heavy metals in seagrasses along Thondi coast,Palk Bay,India

Environmental Science and Pollution Research - The present study deals with the bioaccumulation of heavy metals in different seagrass species (Syringodium isoetifolium, Halodule pinifolia,...     

Isolation of a selected microbial consortium capable of degrading methyl parathion and p-nitrophenol from a contaminated soil site

A bacterial consortium with the ability to degrade methyl parathion and p-nitrophenol, using these compounds as the only carbon source, was obtained by selective enrichment in a medium with methyl parathion. Samples were taken from Moravia, Medellin; an area that is highly contaminated, owing to the fact that it was used as a garbage dump from 1974 to 1982. Acinetobacter sp, Pseudomonas putida, Bacillus sp, Pseudomonas aeruginosa Citrobacter freundii, Stenotrophomonas sp, Flavobacterium sp, Proteus vulgaris, Pseudomonas sp, Acinetobacter sp, Klebsiella sp and Proteus sp were the microorganisms identified within the consortium. In culture, the consortium was able to degrade 150 mg L?1 of methyl-parathion and p-nitrophenol in 120 h, but after adding glucose or peptone to the culture, the time of degradation decreased to 24 h. In soil, the consortium was also able to degrade 150 mg L?1 of methyl parathion in 120 h at different depths and also managed to decrease the toxicity.     

BAF反应器中氨化细菌的筛选与氨化特性分析

以BAF反应器中的生物膜为接种物,分离筛选得到2株氨化细菌,分别命名为A1、A2。通过形态学特征观察、生理生化特性分析及氨化性能进行表征,初步鉴定A1为变形杆菌属（Proteus）,A2为微球菌属（Micrococcus）。生态影响因子实验确定菌株氨化过程主要影响因素是温度、初始pH、投菌量。在30℃、初始pH值7．0,接种量5％的最佳运行条件下,A1、A2两株氨化细菌对有机氮分解效率分别达到86．91％、69．98％。所分离的2株氨化细菌对于高浓度有机氮工业废水的生物降解有一定的应用价值。