RESUMO
Two species of Bacillus, B. thuringiensis B3 and B. cereus B6, isolated from crude oil-contaminated sites in Ecuador, were tested for their capability in degrading polycyclic aromatic hydrocarbons (PAHs) in diesel (shake-flask), and to remove total petroleum hydrocarbons (TPHs) from crude oil- or spent lubricating oil-polluted soils (plot-scale). TPHs and PAHs were analyzed by Gas chromatography-Flame ionization detector (GC-FID) and High performance liquid chromatography (HPLC), respectively. Degradation percentages of PAHs by strain B6 were in the range of 11-83 after 30 days. A mixed culture of both the strains removed 84% and 28% of TPHs from crude oil- and spent lubricating oil-polluted soils, respectively. Reduction in the abundance of total n-alkane fractions (C8-C40) of spent lubricating oil was 94%, which was 18% higher than the control. Our results clearly indicate that the selected strains have great potential in degrading petroleum hydrocarbons at both laboratory- and field-scales.
Assuntos
Bacillus/isolamento & purificação , Poluição por Petróleo/análise , Petróleo/análise , Microbiologia do Solo , Poluentes do Solo/análise , Biodegradação Ambiental , Cromatografia Gasosa , Equador , Ionização de Chama , Hidrocarbonetos/análise , Petróleo/microbiologia , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo/químicaRESUMO
ABSTRACT The wide variety of bacteria in the environment permits screening for more efficient cellulases to help overcome current challenges in biofuels production. This study focuses on the isolation of efficient cellulase producing bacteria found in pulp and paper mill effluent contaminated soil which can be considered for use in large scale biorefining. Four different bacterial strains were isolated and screened for cellulase production by using CMC agar medium. All isolates showed cellulase activity these strains were further characterized by morphological, physiological, biochemical and 16S rRNA gene analyses. These isolates were identified as two Bacillus subtilis sub sps, Bacillus mojavensis and Bacillus cereus.