No abstract

Profiles for polar heteroatom compounds were obtained via Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) using electrospray ionization (ESI) in negative-ion mode for a set of 30 Brazilian oil samples from distinct sedimentary basins and used to estimate biodegradation extents. The samples were initially subjected to traditional geochemical biodegradation analysis to classify them in term of biodegradation levels as based on the Peters and Moldowan scale (PM scale). When the profiles were correlated with the PM scale, it was found that the O1, N, NO2, NO3, and N3O2 classes decrease, whereas the O2, O3, and O4 classes increase in relative abundance with biodegradation. The acyclic to cyclic acids (A/C) ratio of the O2 class, mainly composed of naphthenic acids, provided a robust parameter to classify biodegradation levels of Brazilian oils. A modified saturated acid (SA) index was also used to classify biodegradation levels. For the O1 class, two new monoaromatic (MA) indexes were proposed to predict the biodegradation extent. These MA parameters are based on the most readily degraded phenolic and/or benzylic O compounds by microorganisms and the persistence of O compounds with higher double bond equivalent (DBE) values in more degraded oils.

Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses.

Esta pesquisa foi conduzida para avaliar a qualidade nutricional das refeições consumida pelas crianças, pertencentes à faixa etária de 2 a 6 anos, matriculadas em creches municipais de Teresina. Os dados foram obtidos durante o período de outubro de 1997 a março de 1998, adotando-se o método da pesagem direta dos alimentos. Para o cálculo da adequação nutricional utilizaram-se as médias do consumo de energia e nutrientes, comparadas às recomendações nacionais. O estudo revelou oferta insuficiente de energia, ferro, cálcio e vitamina A, com um consumo protéico e de vitamina C excedendo as recomendações. Os carboidratos contribuíram com 58,5 ± 3,0% das energias totais, as proteínas com 16,0 ± 1,3% e as gorduras com 25,5 ± 3,7%. A deficiência de energia e a inadequação de proteínas e demais nutrientes demonstram a necessidade de um contínuo monitoramento das metas do programa e o aperfeiçoamento do serviço visando à melhoria da qualidade das dietas, com especial atenção ao atendimento das recomendações nutricionais.