Georgiana Feitosa da Cruz

Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs

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.

Bioremediation potential of microorganisms derived from petroleum reservoirs.

Bacterial strains and metagenomic clones, both obtained from petroleum reservoirs, were evaluated for petroleum degradation abilities either individually or in pools using seawater microcosms for 21 days. Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses were carried out to evaluate crude oil degradation. The results showed that metagenomic clones 1A and 2B were able to biodegrade n-alkanes (C14 to C33) and isoprenoids (phytane and pristane), with rates ranging from 31% to 47%, respectively. The bacteria Dietzia maris CBMAI 705 and Micrococcus sp. CBMAI 636 showed higher rates reaching 99% after 21 days. The metagenomic clone pool biodegraded these compounds at rates ranging from 11% to 45%. Regarding aromatic compound biodegradation, metagenomic clones 2B and 10A were able to biodegrade up to 94% of phenanthrene and methylphenanthrenes (3-MP, 2-MP, 9-MP and 1-MP) with rates ranging from 55% to 70% after 21 days, while the bacteria Dietzia maris CBMAI 705 and Micrococcus sp. CBMAI 636 were able to biodegrade 63% and up to 99% of phenanthrene, respectively, and methylphenanthrenes (3-MP, 2-MP, 9-MP and 1-MP) with rates ranging from 23% to 99% after 21 days. In this work, isolated strains as well as metagenomic clones were capable of degrading several petroleum compounds, revealing an innovative strategy and a great potential for further biotechnological and bioremediation applications.

Searching for monooxygenases and hydrolases in bacteria from an extreme environment.

Microbial oxidation potentials of extremophiles recovered from Pampo Sul oil field, Campos Basin, Brazil, in pure culture or in consortia, were investigated using high-throughput screening (HTS) and multibioreactions. Camphor (1), cis-jasmone (2), 2-methyl-cyclohexanone (3), 1,2-epoxyoctane (4), phenylethyl acetate (5), phenylethyl propionate (6), and phenylethyl octanoate (7) were used to perform multibioreaction assays. Eighty-two bacterial isolates were recovered from oil and formation water samples and those presenting outstanding activities in HTS assays were identified by sequencing their 16S rRNA genes. These results revealed that most microorganisms belonged to the genus Bacillus and presented alcohol dehydrogenase, monooxygenase, epoxide hydrolase, esterase, and lipase activities.

Taxonomic Diversity and Biodegradation Potential of Bacteria Isolated from Oil Reservoirs of an Offshore Southern Brazilian Basin

This study aimed at the taxonomic characterization of a collection with 98 bacteria isolated from oil and formation water samples from petroleum reservoirs of the Campos Basin (Brazil), as well as the evaluation of their degradation potential of petroleum biomarkers. The genomic DNA extracted from all isolates was employed in PCR reactions for amplification of the 16S rRNA gene and subsequent screening by ARDRA (Amplified Ribosomal DNA Restriction Analysis), in order to detect potentially distinct taxonomic groups. Further 16S rRNA gene sequencing and phylogenetic analysis of 39 isolates representing different ribotypes revealed that these isolates belonged to 10 different genera, encompassing Marinobacter, Halomonas, Citreicella, Stenotrophomonas, Achromobacter, Bacillus, Staphylococcus, Micrococcus, Kocuria and Streptomyces, affiliated to the three phyla Proteobacteria, Firmicutes and Actinobacteria. RAPD analysis enabled the discrimination of the isolates at the infraspecific level, allowing the identification of 45 distinct genetic band patterns. The chromatographic results showed the preference of all of bacteria to biodegrade nonadecanoic acid and squalane when grown in biomarker mixture. The results of this study provide further insight into the taxonomy of the cultivated fraction of microbial communities of Brazilian oil reservoirs and may offer potential tools for future application in bioremediation processes.

Characterization of Acidic Compounds in Brazilian Tar Sand Bitumens by LTQ Orbitrap XL: Assessing Biodegradation Using Petroleomics

A set of eight tar sand samples with identical source, from sedimentary facies of the Piramboia Formation, Parana Basin, provides an interesting opportunity to assess the biodegradation extent of bitumens using high-resolution mass spectrometry with Orbitrap mass analyzer. The results suggest that acidic compounds have been degraded by microorganisms, since the O2 and O3 classes were lower to bitumens from dry interdune facies, the most biodegraded. It was also proposed a new parameter to evaluate biodegradation, DBE ratio (ratio between acidic species with the same number of double bond equivalent), that was used together with the already proposed A/C ratio (acyclic to cyclic naphthenic acids), both obtained from O2 class distribution. The bitumens from dry interdune facies presented the highest DBE ratios and lowest A/C ratios, which suggested that these parameters can be used to assess the extent of bitumen biodegradation in which the DBE ratios increase and the A/C ratios decrease with increasing biodegradation.

AVALIAÇÃO DO POTENCIAL USO DE BIOGLICERINA COMO BASE PARA FORMULAÇÃO DE FLUIDOS DE PERFURAÇÃO AQUOSOS PARA POÇOS DE PETRÓLEO E GÁS

Cleysson C. Corrêaa, Georgiana F. da Cruza,*, Alexandre S. L. Vaz Jra, Bianca de S. A. Araújoa, Alexsandro A. da Silvab, Rafael A. Rodriguesb , Rosana F. T. Lombac e Alex T. de A. Waldmannc Laboraório de Engenharia e Exploração de Petróleo, Universidade Estadual do Norte Fluminense Darcy Ribeiro, 27.925-535 Macaé – RJ, Brasil Central Analítica Fernanda Coutinho, Instituto de Química, Universidade do Estado do Rio de Janeiro, 20550-900 Rio de Janeiro – RJ, Brasil Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello, Cidade Universitária, 21941-915 Rio de Janeiro – RJ, Brasil

Study of Naphthenic Acidity and Corrosivity of Brazilian Crude Oils by ESI(-) FT-ICR MS

Nos ultimos anos grande parte das reservas de petroleo descobertas no Brasil, com excecao das grandes reservas do pre-sal, bem como em todo o mundo, compreendem oleos de baixo grau API e de alto numero de acidez total (Total Acid Number, TAN). Os acidos naftenicos sao os principais compostos responsaveis por esta elevada acidez, o que leva a muitos problemas na industria petrolifera, tais como a corrosao durante o processo de producao. Neste contexto, o objetivo deste trabalho foi avaliar a acidez naftenica e o potencial corrosivo de 35 amostras de oleos brasileiros utilizando a abundância relativa da classe O2 obtida por espectrometria de massas de ressonância ciclotronica de ions com transformada de Fourier (FT-ICR MS) acoplada a uma fonte de ionizacao por electrospray (ESI) no modo negativo, correlacionando-a com o numero de acidez total (TAN) e a taxa de corrosao em um tipo de aco inoxidavel comumente utilizado em torres de destilacao de refinarias de petroleo. Foi observada uma baixa relacao entre a abundância da classe O2 e o TAN, provavelmente devido a compostos de outras classes heteroatomicas que podem ter contribuido para a acidez total. Alem disso, neste estudo a %O2 se mostrou mais coerente para avaliar a corrosividade dos petroleos avaliados do que o TAN, baseando-se nos testes de corrosao com cupons do aco 316L.

TERPANOS PENTACÍCLICOS COMO INDICADORES DE HETEROGENEIDADES COMPOSICIONAIS EM RESERVATÓRIO DE PETRÓLEO BIODEGRADADO

Reservoir geochemistry has been effectively used to evaluate compositional heterogeneity in petroleum reservoirs by employing oil fingerprinting technique to assess reservoir continuity, primarily in paraffin oil accumulations. In-reservoir biodegradation has resulted in vast deposits of heavy oils globally; therefore, the application of reservoir geochemistry to such accumulations becomes necessary. We recommend the use of pentacyclic terpanes instead of lower molecular compounds, which are less resistant to biodegradation. Using oil fingerprinting technique in this novel way enabled the differentiation of oil composition among sedimentary facies of tar sands (Piramboia Formation, Parana Basin).

Processos naturais de biodegradação do petróleo em reservatórios

Petroleum biodegradation in reservoirs is a process caused by different microorganisms affecting many oil deposits which modifies the oil composition in a quasi-stepwise process starting from n-alkanes and isoprenoids through to diasteranes. This causes oil souring and increased viscosity, sulfur and metal content, having a direct impact on oil production and refining costs.