Haloalkalitolerant Actinobacteria with capacity for anthracene degradation isolated from soils close to areas with oil activity in the State of Veracruz, Mexico

The use of native strains of microorganisms from soils is an excellent option for bioremediation. To our knowledge, until now there has been no other group working on the isolation of Actinobacteria from contaminated soils in Mexico. In this study, samples of soils close to areas with oil activity in the State of Veracruz, Mexico, were inoculated for the isolation of Actinobacteria. The strains isolated were characterized morphologically, and the concentrations of NaCl and pH were determined for optimal growth. Strain selection was performed by the detection of a phylogenetic marker for Actinobacteria located at the 23S rRNA gene, followed by species identification by sequencing the 16S rRNA gene. Several haloalkalitolerant Actinobacteria were isolated and identified as: Kocuria rosea, K. palustris, Microbacterium testaceum, Nocardia farcinica and Cellulomonas denverensis. Except for C. denverensis, the biomass of all strains increased in the presence of anthracene. The strains capacity to metabolize anthracene (at 48 h), determined by fluorescence emission, was in the range of 46-54%. During this time, dihydroxy aromatic compounds formed, characterized by attenuated total reflectance Fourier transform infrared spectroscopy bands of 1205 cm-1 and 1217 cm-1. Those Actinobacteria are potentially useful for the bioremediation of saline and alkaline environments contaminated with polycyclic aromatic hydrocarbon compounds (AU)

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Coeficientes de partición de hidrocarburos aromáticos policíclicos con sustancias húmicas: un método simple para su determinación / Binding coefficients of polycyclic aromatic hydrocarbons to humic substances: a simple method for their determination

Las sustancias húmicas son componentes importantes de las aguas naturales, son polímeros ácidos, predominantemente aromáticos, que no resultan nocivos a los seres vivos. Sin embargo, su rol en el medio ambiente es importante porque afectan a la biodisponibilidad y toxicidad de muchos compuestos en el ambiente acuático. Por otra parte, entre los contaminantes de los sistemas acuáticos, se hallan los hidrocarburos aromáticos policíclicos (HAPs), algunos de los cuales son cancerígenos. Esta serie de compuestos en general está presente en el ambiente como mezclas complejas, presentando un rango muy variado de propiedades químicas, físicas y toxicológicas. En el presente trabajo, se estudió la interacción de sustancias húmicas con fenantreno y antraceno, separados o en mezcla, determinándose los coeficientes de partición (Koc) de las sustancias entre el carbono orgánico disuelto y la fase líquida por una metodología sencilla que utiliza extracción en fase sólida y determinación por espectrofotometría UV-visible. Los valores de Koc obtenidos son comparables con los referidos para estos compuestos por aplicación de otras técnicas. El método descrito es una herramienta que puede ser útil para analizar la interacción de los contaminantes orgánicos hidrofóbicos con las sustancias húmicas

Humic substances are major components of natural water. They are acidic polymers, mostly aromatic and usually harmless. However, they play an important role because they affect bioavailability and toxicity of many compounds in aquatic environments. Polycyclic aromatic hydrocarbons (some of them carcinogenic) are considered to be some of the most common pollutants of aquatic systems. They are usually found in the environment as complex mixtures exhibiting a wide range of physical, chemical and toxicological properties. In the present work, the interaction between humic substances and phenantrene and anthracene, individually or in mixtures, was studied. Partition coefficients of the substances between dissolved organic carbon and liquid phase were estimated by a simple methodology involving solid phase extraction and UVVIS spectrophotometry. Koc values obtained by this means are comparable with those obtained using other methods. The method described is a valuable tool for analyzing interactions of hydrophobic pollutants with humic substances