RESUMEN
This paper presents a study of the effect of a combined biostimulation-bioaugmentation treatment applied to a clay-loam soil contaminated with 16,300 mg/kg of total petroleum hydrocarbons (TPH), which comprised 51% saturated hydrocarbons and 31% aromatic hydrocarbons. The bioaugmentation was performed with yeast Candida tropicalis SK21 isolated from petroleum-contaminated soil. The strain was able to grow in a pH range of 3-9 in liquid culture, and the optimum pH was found to be 6 for both growth and biosurfactant production. At pH 6, 96% and 42% of TPH were degraded by the strain at the initial diesel oil concentrations of 0.5% and 5% (v/v), respectively. The remediation via inoculating the yeast removed 83% of TPH in 180 days while the experiment with the indigenous microorganisms alone removed 61%. Microbial enumeration showed that the yeast SK21 could grow good in the soil. It was also found that dehydrogenase and polyphenoloxidase activities in soil were remarkably enhanced by the inoculation of the yeast.
Asunto(s)
Candida tropicalis/clasificación , Candida tropicalis/fisiología , Petróleo/microbiología , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Eliminación de Residuos Líquidos/métodos , Biodegradación Ambiental , Proliferación Celular , Supervivencia Celular , Petróleo/análisis , Contaminantes del Suelo/aislamiento & purificación , Especificidad de la EspecieRESUMEN
Two new ent-kaurene diterpenoids, 15α-acetoxyl-6,11α-epoxy-6α-hydroxy-20-oxo-6,7-seco-ent-kaur-16-en-1,7-olide (1), 15α-hydroxy-20-oxo-6,7-seco-ent-kaur-16-en-1,7α(6,11α)-diolide (2), together with ten known compounds (5-14) were isolated from the leaves of Isodon rubescens. Their structures were elucidated mainly by various spectroscopic techniques and finally confirmed by single-crystal X-ray diffraction. Compounds 1, 2, 8 and 12 were evaluated for their cytotoxicities against EC-1, U87, A549, MCF-7 and Hela cell lines.
