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Little is known about the ability of methanogens to grow and produce methane in estuarine environments. In this study, traditional methods for cultivating strictly anaerobic microorganisms were combined with Fluorescence in situ hybridization (FISH) technique to enrich and identify methanogenic Archaea cultures occurring in highly polluted sediments of tropical Santos-São Vicente Estuary (São Paulo, Brazil). Sediment samples were enriched at 30 degrees C under strict anaerobic and halophilic conditions, using a basal medium containing 2% of sodium chloride and amended with glucose, methanol, and sodium salts of acetate, formate and lactate. High methanogenic activity was detected, as evidenced by the biogas containing 11.5 mmol of methane at 20 days of incubation time and methane yield of 0.138-mmol CH(4)/g organic matter/g volatile suspense solids. Cells of methanogenic Archaea were selected by serial dilution in medium amended separately with sodium acetate, sodium formate, or methanol. FISH analysis revealed the presence of Methanobacteriaceae and Methanosarcina sp. cells.

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The anaerobic biological treatment of pentachlorophenol (PCP) and methanol as the main carbon source was investigated in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor at 30+/-1 degrees C, during a 220-day trial period. The reactor biomass was developed as an attached biofilm on polyurethane foam particles, with 24h of hydraulic retention time. The PCP concentrations, which ranged from 2.0 to 13.0 mg/L, were controlled by adding synthetic substrate. The HAIB reactor reduced 97% of COD and removed 99% of PCP. The microbial biofilm communities of the HAIB reactor amended with PCP, without previous acclimatization, were characterized by polymerase chain reaction (PCR) and amplified ribosomal DNA restriction analysis (ARDRA) with specific Archaea oligonucleotide primers. The ARDRA technique provided an adequate analysis of the community, revealing the profile of the selected population along the reactor. The biomass activities in the HAIB reactor at the end of the experiments indicated the development of PCP degraders and the maintenance of the population of methanogenic Archaea, ensuring the high efficiency of the system treating PCP with added methanol as the cosubstrate. The use of the simplified ARDRA method enabled us to monitor the microbial population with the addition of high concentrations of toxic compounds and highlighting a selection of microorganisms in the biofilm.

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Legionella species are ubiquitous bacteria in aquatic environments. To examine the effect of anthropogenic impacts and physicochemical characteristics on the Legionellaceae population, we collected water from two sites in the Itanhaém River system in the Atlantic Forest of Brazil. One sample was collected from an upstream pristine region, the other from a downstream estuarine region moderately affected by untreated domestic sewage. Cultures on a selective medium failed to isolate Legionella species. Culture-independent methods showed that water from the estuarine aquatic habitat contained DNA sequences homologous to the 16S ribosomal DNA gene of Legionella pneumophila and non-pneumophila species. In pristine water, only two sequences related to L. pneumophila were detected. The results suggest that salinity and anthropogenic factors, such as wastewater discharge, favor a diversity of Legionella species, whereas pristine freshwater selects for Legionella pneumophila.

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Wastewater samples from an anaerobic reactor were extracted with hexane and derivatized with diazomethane (method 1) and with acetic anidride (method 2). Gas chromatography with electron-capture detection (ECD) was employed for separating the parent compound and intermediates trichlorophenols (TCP) and dichlorophenols (DCP) which originated from the penta chlorophenol (PCP) degradation process. The relations between concentrations of PCP, TCP and DCP areas were linear in the range of concentrations of 0.2 to 8 mg/L and 0.025 mg/L to 5 mg/L for methods 1 and 2, respectively. The repeatability of the extraction methods was satisfactory, with variation coefficients lower than 11%. For method 1, at the fortification level of 0.2 mg/L, recovery of PCP, TCP, and DCP was 112%, 74% and 45%, respectively. For method 2, the corresponding recovery values at the fortification level of 0.1 mg/L were 91%, 93% and 103%, respectively. Storage of the frozen samples did not alter their PCP determination properties. The chromatographic methods adapted for chlorophenol determination in wastewater were suitable with relatively simple manipulation techniques. The obtained results were reproducible and allowed identification of intermediates formed during the PCP degradation process.

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We present a fast procedure for scanning electron microscopy (SEM) analysis in which hexamethyldisilazane (HMDS) solvent, instead of the critical point drying, is used to remove liquids from a microbiological specimen. The results indicate that the HMDS solvent is suitable for drying samples of anaerobic cells for examination by SEM and does not cause cell structure disruption.

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Durante um ano foi realizado o monitoramento da biodegradabilidade anaeróbia de resíduos sólidos, do potencial de geração de metano e da composição microbiológica de dois aterros sanitários experimentais. Observou-se que, apesar da grande heterogeneidade dos resíduos sólidos, os resultados em termos de estabilização de matéria orgânica durante a fase de produção de metano foram similares para os dois aterros. Ambos os sistemas apresentaram as mesmas faixas de produção de metano (91.5 L CH4 / kg STV - sólidos totais voláteis) e de ácidos orgânicos, principalmente ácidos acético e butírico. Isolou-se ainda, culturas bacterianas dos gêneros Megasphaera, Selenomonas, Methanobacterium, Methanobrevibacter and Methanosarcina.

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Solid wastes anaerobic biodegradability, methane production potential and microbiological composition of two experimental sanitary landfills in Brazil, running for one year, were evaluated. The two landfills showed a similar organic matter stabilization during the methane production phase, despite the high heterogeneity of the solid wastes. Both landfills presented the same level of methane (around 91.5 L CH4 / kg Volatile Total Solids) and organic acids, mainly acetic and butyric acids, in the leachate. Bacterial isolates belonged to genera Megasphaera, Selenomonas, Methanobacterium, Methanobrevibacter and Methanosarcina.

Durante um ano foi realizado o monitoramento da biodegradabilidade anaeróbia de resíduos sólidos, do potencial de geração de metano e da composição microbiológica de dois aterros sanitários experimentais. Observou-se que, apesar da grande heterogeneidade dos resíduos sólidos, os resultados em termos de estabilização de matéria orgânica durante a fase de produção de metano foram similares para os dois aterros. Ambos os sistemas apresentaram as mesmas faixas de produção de metano (91.5 L CH4 / kg STV - sólidos totais voláteis) e de ácidos orgânicos, principalmente ácidos acético e butírico. Isolou-se ainda, culturas bacterianas dos gêneros Megasphaera, Selenomonas, Methanobacterium, Methanobrevibacter and Methanosarcina.

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No presente trabalho propöe-se uma metodologia alternativa àquela descrita no Manual de Testes para Avaliaçäo da Ecotoxicidade de Agentes Químicos do IBAMA, para avaliaçäo da biodegradaçäo de agrotóxicos em amostras de solos. Utilizando-se a trifluralina como modelo, foi feita a avaliaçäo da biodegradaçäo deste agrotóxico em solo do Estado de Säo Paulo, a partir da detecçäo e determinaçäo quantitativa da trifluralina por cromatografia gasosa de alta resoluçäo com detecçäo por ionizaçäo de chama (HRGC/FID) os resultados encontrados foram compatíveis com o comportamento da trifluralina em solos, determinado por métodos radiométricos e descrito na literatura para a trifluralina. A substituiçäo do método convencional (radiométrico) pelo método cromatográfico pode ser uma alternativa mais econômica e mais conveniente para a realidade brasileira.

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Säo descritos métodos e procedimentos de preservaçäo de bactérias anaeróbias estritas produtoras de metano. Duas técnicas diferentes foram adotadas: uma para manutençäo de baixo potencial de oxireduçäo em frascos de cultivo e outra para conservaçäo das células bacterianas em nitrogênio líquido

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