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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Calagem e adubação fosfatada favorecem o crescimento do capim-limão, Cymbopogon citratus (DC) Stapf / Liming and phosphate fertilization promote lemongrass, Cymbopogon citratus (DC) Stapf. growth

O capim-limão, Cymbopogon citratus (DC) Stapf., é uma planta utilizada para fins medicinais e aromáticos, porém pouco se conhece sobre as exigências nutricionais. O objetivo do presente trabalho foi avaliar os efeitos da elevação do pH do solo e da adubação com fósforo (P) na disponibilidade de nutrientes e no crescimento inicial do capim-limão. O experimento foi conduzido em Lages, SC, de abril a dezembro de 2008, em casa de vegetação. Foi utilizado um esquema fatorial, incluindo quatro níveis de pH (4,1; 5,5; 6,0 e 6,5) e três doses de P (0, 50 e 100 mg kg-1 de solo), com quatro repetições (correspondendo a um vaso com duas plantas). A correção do pH aumentou o Ca e Mg e diminuiu o Al, Mn, Fe, Cu e Zn no solo. A aplicação de 100 mg kg-1 de P elevou em mais de 250% a concentração deste nutriente no solo, independente do pH. A aplicação de P e, principalmente, a elevação do pH do solo incrementaram todos os atributos avaliados nas plantas de capim limão (massa seca da parte aérea e do sistema radicular, número de folhas e altura de plantas), sendo que a interação entre pH e dose de P somente foi significativa para o número de folhas. O maior crescimento das plantas ocorreu no tratamento com pH 6,5, associado à adição de 100 mg kg-1 de P.

Lemongrass, Cymbopogon citratus (DC) Stapf., is a plant with medicinal and aromatic uses. However, little is known about its nutrition requirements. This work was carried out to investigate the effects of pH and phosphorus levels on nutrients availability and the initial growth of lemongrass. The experiment was carried out in Lages (SC, Brazil) from April tol December 2008, in greenhouse conditions. The experiment followed a factorial design, with four levels of pH (4.1, 5.5, 6.0, and 6.5), three doses of phosphorus (0, 50, and 100 mg kg-1 of soil), and four replicates (each replicate corresponding to a pot with two plants). The correction of pH increased Ca and Mg, and reduced Al, Mn, Fe, Cu, and Zn in the soil. The addition of 100 mg kg-1 P increased by more than 250% the P in the soil, irrespective of pH. The addition of P and the correction of pH, specially the last one, increased all growth attributes of lemongrass (dry matter of shoot and root parts, number of leaves, and plant height), with a significant interaction between pH and the dose of P only for the number of leaves. The highest plant growth was achieved by correcting the soil pH to 6.5, with the addition of 100 mg kg-1 P.