Biodegradation of biodiesel/diesel blends by Candida viswanathii

This work is aimed to assess the aerobic biodegradation of biodiesel/diesel blends (0, 2, 5, 20 and 100%, v/v) by Candida viswanathii. The biodegradation potential of the inoculum was assessed with the redox indicator 2,6-dichlorophenol indophenol (DCPIP) test and with respirometric experiment in biometer flasks (250 mL) used to measure the microbial CO(2) production. In the latter, the inoculum was added to a contaminated soil with the blends (addition of 50 mL of fuel/Kg of soil from a non-contaminated site). C. viswanathii was able to increase significantly (approximately 50% in terms of CO(2) production) the biodegradation in soil of biodiesel/diesel blends and neat biodiesel since it preferable biodegrades biodiesel. Without inoculum the biodegradation of diesel oil was higher than biodiesel and blends (47.3, 51.1, 5.7 and 22.1% in terms of CO(2) production by B2, B5, B20 and B100, respectively) presumably due to the presence of the antioxidant terc-butyl-hydroquinone (TBHQ) in the biodiesel.

Aplicação da técnica de caminhamento elétrico em área contaminada por derivados de petróleo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Uso de reações de fenton na remediação de solo contaminado com p,p´ DDT

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical structure, surface properties and biological activities of the biosurfactant produced by Pseudomonas aeruginosa LBI from soapstock

Pseudomonas aeruginosa LBI isolated from petroleum-contaminated soil produced rhamnolipids (RLLBI) when cultivated on soapstock as the sole carbon source. HPLC-MS analysis of the purified culture supernatant identified 6 RL homologues (%): R-2 C-10 C-10 28.9; R-2 C-10 C-12:1 23.0; R-1 C-10 C-10 23.4; R-2 C-10 C-12 11.3; R-2 C-10 C-12 7.9; R-2 C-10 C-12 C-12 5.5. To assess the potential antimicrobial activity of the new rhamnolipid product, RLLBI, its physicochemical properties were studied. RLLBI had a surface tension of 24 mN m(-1) and an interfacial tension 1.31 mN m(-1); the cmc was 120 mg l(-1). RLLBI produced stable emulsions with hydrocarbons and vegetable oils. This product showed good antimicrobial behaviour against bacteria: MIC for Bacillus subtilis, Staphylococcus aureus and Proteus vulgaris was 8 mg l(-1), for Streptococcus faecalis 4 mg l(-1), and for Pseudomonas aeruginosa 32 mg l(-1). RLLBI was active against phytopathogenic fungal species, MIC values of 32 mg l(-1) being found against Penicillium, Alternaria, Gliocadium virens and Chaetonium globosum. Due to its physicochemical properties and antimicrobial behaviour, RLLBI could be used in bioremediation treatment and in the food, cosmetic and pharmaceutical industries.

Rhamnolipid production by Pseudomonas aeruginosa LBI growing on soapstock as the sole carbon source

A new bacterial strain, was isolated from petroleum contaminated soil, identified and named Pseudomonas aeruginosa strain LBI. The new strain produced surface-active rhamnolipids by batch cultivation in a mineral salts medium with soapstock as the sole carbon source. Biosurfactant production increased after nitrogen depletion. The maximum rhamnolipid concentration, 15.9 g/l, was reached when it was incubated in a bioreactor with a constant K(L)a of 169.9 h(-1). (C) 2002 Elsevier B.V. Ltd. All rights reserved.

In Vitro Susceptibility of Environmental Isolates of Exophiala dermatitidis to Five Antifungal Drugs

Several dematiaceous fungi frequently isolated from nature are involved in cases of superficial lesions to lethal cerebral infections. Antifungal susceptibility data on environmental and clinical isolates are still sparse despite the advances in testing methods. The objective of this study was to examine the activities of 5-flucytosine, amphotericin B, itraconazole, voriconazole and terbinafine against environmental isolates of Exophiala strains by minimum inhibition concentration (MIC) determination. The strains were obtained from hydrocarbon-contaminated soil, ant cuticle and fungal pellets from the infrabuccal pocket of attine gynes. Broth microdilution assay using M38-A2 reference methodology for the five antifungal drugs and DNA sequencing for fungal identification were applied. Terbinafine was the most active drug against the tested strains. It was observed that amphotericin B was less effective, notably against Exophiala spinifera, also studied. High MICs of 5-flucytosine against Exophiala dermatitidis occurred. This finding highlights the relevance of studies on the antifungal resistance of these potential opportunistic species. Our results also contribute to a future improvement of the standard methods to access the drug efficacy currently applied to black fungi. © 2012 Springer Science+Business Media Dordrecht.

Frequency and genetic diversity of the MAT1 locus of Histoplasma capsulatum isolates in Mexico and Brazil

The MAT1-1 and MAT1-2 idiomorphs associated with the MAT1 locus of Histoplasma capsulatum were identified by PCR. A total of 28 fungal isolates, 6 isolates from human clinical samples and 22 isolates from environmental (infected bat and contaminated soil) samples, were studied. Among the 14 isolates from Mexico, 71.4% (95% confidence interval [95% CI], 48.3% to 94.5%) were of the MAT1-2 genotype, whereas 100% of the isolates from Brazil were of the MAT1-1 genotype. Each MAT1 idiomorphic region was sequenced and aligned, using the sequences of the G-217B (+mating type) and G-186AR (-mating type) strains as references. BLASTn analyses of the MAT1-1 and MAT1-2 sequences studied correlated with their respective+ and-mating type genotypes. Trees were generated by the maximum likelihood (ML) method to search for similarity among isolates of each MAT1 idiomorph. All MAT1-1 isolates originated from Brazilian bats formed a well-defined group; three isolates from Mexico, the G-217B strain, and a subgroup encompassing all soil-derived isolates and two clinical isolates from Brazil formed a second group; last, one isolate (EH-696P) from a migratory bat captured in Mexico formed a third group of the MAT1-1 genotype. The MAT1-2 idiomorph formed two groups, one of which included two H. capsulatum isolates from infected bats that were closely related to the G-186AR strain. The other group was formed by two human isolates and six isolates from infected bats. Concatenated ML trees, with internal transcribed spacer 1 (ITS1) -5.8S-ITS2 and MAT1-1 or MAT1-2 sequences, support the relatedness of MAT1-1 or MAT1-2 isolates. H. capsulatum mating types were associated with the geographical origin of the isolates, and all isolates from Brazil correlated with their environmental sources. © 2013, American Society for Microbiology. All Rights Reserved.

Avaliação de processos de caracterização e remediação de passivos ambientais de contaminação por hidrocarbonetos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da produção de biossurfactantes utilizando hidrocarbonetos

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Avaliação ecotoxicológica da biodegradação utilizando inóculo enriquecido com Bacillus subtilis em solo contaminado com petróleo, diesel e biodiesel

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Amenizantes em solo contaminado com bário

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Um estudo da formação de disponibilidade de piromorfita (Pb 5(PO4)3OH) em solos contaminados com Pb e remediados com NH4H2PO4

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bactérias produtoras de biossurfactantes: isolamento, produção, caracterização e comportamento num sistema modelo

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Polihidroxialcanoatos (PHAs): bioprospecção de micro-organismos e produção a partir de glicerol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mucorales de solo contaminado com metais pesados na região do pólo cerâmico de Santa Gertrudes, SP: ocorrência e capacidade de biossorção de chumbo e zinco

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC