Selected Native Microorganisms from Hydrocarbon Polluted Soils in Ecuador, Potentially Useful for Bioremediation Processes

In Ecuador new politics of environmental protection are encouraged, and the use of innovation processes such as bioremediation of contaminated matrices with microorganisms is supported. In the process of biodegradation some microorganisms can use oil or its derivates as the only source of carbon for energy supply. The main objective of this investigation is obtaining a sustainable system for the hydrocarbon polluted soil bioremediation in Ecuador. Effectiveness of two native bacteria in the bioremediation of residual oil (bunker oil) polluted soil was tested in vitro and in mesocosm. Five soil samples were collected in a thermoelectric power plant in Cuenca -- Ecuador (2350 m a.s.l.). Chemical analyses were carried out on PHA content. Bacteria were isolated by means of soil dilution plates and sprinkled plate techniques on PDA and TSA at 28°C. Twenty bacterial strains were isolated and screened for their capacity of growing on bunker oil as the only source of carbon. A Streptomyces sp. and a bacillus encoded as B8 were selected and used single or in consortium, consortia were formed based on the biodegradation capacity and bunker tolerance of the microorganisms. The in vitro experiment ran in 250 ml bottles containing mineral medium or TS with PHA dissolved in tween 80. PHA breakdown was evaluated after 3 months by gas chromatography analysis. Statistically significant results on percentage of biodegradation were obtained, particularly on naphthalene (99.02%), phenanthrene (99, 79 %), B (b) Fluoranthene (97, 76%), B (K) Fluoranthene (97, 74 %), B (g, h, i) Perylene (97.77 %). Biodegradation of PHA was also tested in experiments performed in mesocosm under ambient condition, using polluted soil collected from the thermoelectric power site. Similar results to those obtained in vitro were recorded.