Metalworking fluids (MWFs) are petroleum emulsions employed for metal machining processes as coolants and lubricants. To date, they have been irreplaceable in modern heavy and manufacturing industries, with annual usage exceeding two billion litres worldwide. However, the large amount of MWFs, the highly concentrated complex recalcitrant and toxic petroleum components contained in them continue to cause significant concern in terms of sustainable routes of end-of-life treatment and disposal. Compared with other treatment methods, the anaerobic treatment method has significant advantages, such as the low capital, operating and maintenance costs and energy recovery. This latter factor has the potential benefit of generating bio-energy from waste organic matter whilst aerobic route leads to CO₂ emission. However, the bio-toxicity of MWFs is a huge challenge in terms of employing bio-treatment of waste MWFs. In this study, the anaerobic biodegradability of a typical MWF was investigated employing an activated sludge experimental system. Furthermore, the toxic effects of the MWF on the anaerobic ecosystem, particularly on methanogen species, were investigated using bio-molecular analytical methods and a biosensor. In order to overcome its toxicity, the indigenous anaerobic bacteria isolated from spent MWFs were employed in the treatment of the MWF since they were assumed to be acclimated to the conditions. The major findings include: (1) approximately 80% of the MWF (5,000mgCOD/L) was found to be anaerobically biodegradable, with around 35% of the biodegraded COD could be converted to methane; (2) the MWF appeared to be toxic to the anaerobic ecosystem, especially to methanogen species; and (3) however, treatment employing the anaerobic bacteria successfully reduced the toxicity of the MWF and enhanced the methane production in the process.

Na presente pesquisa, utilizou-se a técnica molecular de Eletroforese em Gel de Gradiente Desnaturante (DGGE) e microscopia óptica (contraste de fase e fluorescência) para caracterizar a comunidade procarionte estabelecida em quatro biometanizadores de 50 L e em três biometanizadores de 5 L, cujo substrato principal foi a fração orgânica dos resíduos sólidos urbanos (FORSU) acrescida de serragem (12% nos biometanizadores de 50 L e 20% nos de 5 L) e lodo de esgoto (9% e 18% nos biometanizadores de 50 L; 40% e 60% nos de 5L). Pela análise do perfil das bandas de DGGE, verificou-se uma alteração na estrutura da comunidade de bactérias presentes no chorume dos biometanizadores de 50 L entre 60 e 120 dias de operação, período caracterizado pelo acúmulo de ácidos graxos voláteis, consumo crescente de alcalinidade, queda de pH e aumento da demanda química de oxigênio, resultando na baixa remoção de sólidos totais voláteis e na ausência de metano no biogás. Pela análise de microscopia de fluorescência, não foram detectadas metanogênicas em nenhuma das amostras de chorume dos biometanizadores de 50 L, sendo que as principais morfologias e formas de agrupamento visualizadas foram: bacilo, diplobacilos, vibrião, espirilo, diplococos e cocos em cadeia. Os biometanizadores de 5 L, por serem inoculados com maiores proporções de lodo de esgoto do que os biometanizadores de 50 L, apresentaram um processo mais equilibrado. Um dos tratamentos de 5 L (ETE 2) obteve a maior similaridade para o domínio Archaea entre o digestato e o respectivo inóculo, demonstrando a adaptação das arqueas exógenas ao substrato principal (FORSU), sendo esse o único tratamento para o qual detectou-se metano no biogás. Os resultados sugeriram que monitorar a comunidade microbiana que se desenvolve e atua no processo de biometanização pode trazer maior sensibilidade e especificidade na detecção e confirmação de instabilidades do sistema, garantindo intervenções somente quando necessário. / This dissertation addresses the use of the molecular technique of Denaturing Gradient Gel Electrophoresis (DGGE) and light microscopy (phase contrast and fluorescence) for the characterization of the prokaryotic community established in four 50 L reactors and in three 5 L reactors whose main substrate was the organic fraction of municipal solid wastes (OFMSW) plus sawdust (12% in 50 L reactors and 20% in 5 L reactors) and sewage sludge (9% and 18% in 50 L reactors; 40% and 60% in 5 L reactors). The analysis of the profile of DGGE bands revealed a change in the structure of the bacterial community present in the slurry of 50 L reactors between 60 and 120 days of operation, a period characterized by the accumulation of volatile fatty acids, increasing consumption of alkalinity, decrease in pH and increase in the chemical oxygen demand, which resulted in a lower removal of volatile total solids and absence of methane in the biogas. The fluorescence microscopy analysis detected no methanogenics in the slurry samples from 50 L reactors and the main morphologies and grouping forms displayed were bacillus, diplobacilos, vibrio, spirillum, diplococci and coconuts in chain. The 5 L reactors, inoculated with higher proportions of sewage sludge than the 50 L reactors, showed a more balanced process. One of the treatments (ETE 2) displayed the highest similarity for the Archaea domain between the digestato and the respective inoculum, which demonstrates the adaptation of the exogenous archaea to the main substrate (OFMSW). It was the only treatment in which methane was detected in the biogas. The results suggest the monitoring of the microbial community that develops and acts in the biomethanization process can provide higher sensitivity and specificity for the detection and confirmation of instability of the system and ensure interventions only when necessary.

Remediation of trichloroethylene (TCE) is a major priority for many contaminated sites all over the industrialized world including Hill Air Force Base, UT (HAFB). Phytoremediation as part of a cleanup strategy is an appealing option, and trees at HAFB have been studied to this end. Trees have also been used to delineate groundwater plumes because the passive uptake of organic contaminants by trees generally results in a direct relationship between tree and groundwater TCE concentrations if the trees are using the contaminated groundwater. However, the concentrations of plant-produced TCE metabolites can vary greatly. It was hypothesized that the endophytic microbial community present may be affecting the fate of TCE within these trees. This study was designed to determine if the microbial community present within hybrid poplar trees would change in response to TCE exposure. Trees were grown in a greenhouse to reduce environmental variability. Concentrations of TCE, its degradation products, and its metabolites were then measured in these trees. DNA was extracted from the tree tissues and amplified to determine the quantity of microbial DNA. Diversity of this DNA was determined by fragment analysis. Data were analyzed to determine if there was an effect of TCE treatment on the microbial community composition in the trees. Results showed that all tissues of dosed trees contained TCE. Metabolism of TCE to trichloroacetic acid (TCAA) and trichloroethanol (TCEtOH) in tree tissues was observed by the accumulation of these metabolites. Microbial DNA results revealed that TCE treatment reduced both the quantity and diversity of endophytic bacteria and fungi in several cases. Multivariate statistical analyses also showed that the endophytic microbial community shifted in response to TCE treatment. The endophytic microbial communities present in the hybrid poplar trees of this study were high in concentration and diversity, both of which were affected by TCE treatment. Endophytic bacterial concentrations were observed at over 109 copies/g with diversities of 70+ genetically distinct organisms. Decreases in these values with the addition of TCE showed that the community dramatically changed in some cases, but was able to more quickly adapt to TCE addition in other cases. The effects of these endophytic microorganisms associated with plants should therefore be included when phytoremediation is considered.

No description available.

<p>The Eastern Antarctic Dry Valley region is a polar desert, where conditions of extreme aridity, high temperature fluctuations and high irradiation levels make it one of the most extreme environments on earth. Despite the harsh environment, the soils in this region yield a wide range of bacterial and eukaryotic phylotypes in greater abundance than previously believed. In the Dry Valleys, highly localized niche communities colonise the underside of translucent quartz rocks and present macroscopic growth.</p>

The methods of denaturing gradient gel electrophoresis (DGGE) and DNA sequencing were used to analyze the ribotypes of microbial communities associated with corals. Both healthy and diseased coral of different species were collected at three locations off the southern coast of Taiwan. Ribotyping results suggested that the microbial communities were diverse. The microbial community profiles, even among the same species of corals from different geographical locations or different times, differ significantly. The coral-associated bacterial communities contain many bacteria common to the habitants of various invertebrates. One ribotype presented on the Black Disease coral tissue is closely related to the Clostridium sp. previously identified from White Plaque-diseased and BBD corals. This Clostridium sp. may be relatived to coral diseased, as this species was also found in many types of diseased coral. The other one ribotype presented on our healthy and diseases coral is closed to denitrifying bacterium Pseudovibrio sp. which had been previously discovered in Kenting National Park Nanwan Bay as a new marine, facultative anaerobic bacterium. However, some bacteria were unexpected. The presence of some unusual species, such as Staphylococcus, Legionella and soil bacteria, associated with corals that were likely the results of human activities. Human activities, such as active fishing and tourism industries in the region might have all contributed to the change in bacterial communities and the death of coral colonies around the region.

In Taiwan, more than 20% of the major rivers are mildly to heavily pollute by domestic, industrial, and agricultural wastewaters due to the low hook-up rate of public underground sewerage systems in rural areas. Thus, constructed or engineered wetlands have been adopted as the major alternatives to cleanup polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems to polish the secondary wastewater effluents to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before they discharge into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks of organics and metals. In this study, water, sediment and macrophytes samples were collected from the major wetland basins in KRRBCW. The quarterly investigation (from 2007 to 2009) results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g., total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g., Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O2/m2-d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TP). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that an increase in microbial diversities in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of microbial ribospecies, which might contribute to the carbon degradation and nitrogen removal. Gradually disappearing of E. coli was also observed along the flow courses through the natural attenuation mechanisms. The factor analysis of SPSS 12.0 shows that 17 water-quality items of the study site could obtain four to six principal components, including nitrate factor, phosphorus factor, eutrophication factor, organic factor, and environmental background factor, the major influencing components are nutrition factor and eutrophication factor. The ponds of the study site were classified into two or three clusters depend on in-and-out flow location. This study attempted to establish a forecasting model of wetland pollutants concentration through the time series (ARIMA), results show that the outcome of the B7 pond was better than others. Results indicate that the ARIMA model can be used to simulate the trend of treatment efficiency using the wetland system. Experience and results obtained from this study would provide solutions for water quality control. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for public, and rORPabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.

The effect of simple and complex on the composition and diversity of microbial communities and on end-product (biogas and VFAs) synthesis was investigated using an anaerobic batch respirometer at 37 °C and pH 7.2. These experiments, simple substrates were chemically pure and contain a single carbon source (glucose or α-cellulose), while complex substrates were chemically “impure” substrates containing a mixture of two or three carbon sources (biodiesel-derived glycerol or wheat straw) with a substrate/inoculum ratio 6g chemical oxygen demand (COD)/ g volatile solids (VS) seed and 100g of pre-treated dairy manure digestate (DMD), respectively. Concentrations of hydrogen, carbon dioxide, acetate, butyrate, propionate, and ethanol synthesized by different communities selected by growth on the different substrates were measured and confirmed the growth of the microbial communities. 16S rDNA illumina sequencing revealed that DMD without substrates was more diverse than the microbiota cultured by fermentation reactions containing D-glucose, glycerol α-cellulose or wheat straw. The data confirmed that substrates play a crucial role in determining the diversity of species in microbial communities. Dominant operational taxonomic units (OTUs) belonging to families Clostridiaceae, Ruminococcaceae, and Enterobacteriaceae, and the genera Clostridium, Ruminococcus, Sporolactobacillus, and Syntrophomonas were potentially responsible for changes in end-product synthesis patterns in communities cultured with simple and complex substrates. / October 2015

<p>The Eastern Antarctic Dry Valley region is a polar desert, where conditions of extreme aridity, high temperature fluctuations and high irradiation levels make it one of the most extreme environments on earth. Despite the harsh environment, the soils in this region yield a wide range of bacterial and eukaryotic phylotypes in greater abundance than previously believed. In the Dry Valleys, highly localized niche communities colonise the underside of translucent quartz rocks and present macroscopic growth.</p>

Microbial mats exist in freshwater pools atop the Ward Hunt and Markham ice shelves in the Canadian high Arctic. In this study, culture-dependent and culture-independent techniques were used to describe the microbial diversity and activity of these mat communities.Bacterial and archaeal 16S rRNA gene clone libraries were constructed from Markham and Ward Hunt mat samples. Bacterial libraries from both mats had high diversity, though the Markham library appeared more diverse than the Ward Hunt library. Over 95% of sequences in both bacterial libraries, and all isolates from both mats, grouped within the phyla Bacteroidetes, Proteobacteria, and Actinobacteria. Archaeal diversity appeared low in both mats. Only one phylotype, potentially representing a novel Euryarchaeota, was observed in both archaeal libraries. Populations in both communities showed activity at subzero temperatures, with growth of isolates at -5°C and detectable metabolic activity at -10°C, measured by radiorespiration assays of mat microcosms.