Removal of petroleum hydrocarbons from crude oil in solid and slurry phase by mixed soil microorganisms isolated from Ecuadorian oil fields

Soil collected from oil fields of the Ecuadorian Amazon rainforest contained microorganisms capable of removing total petroleum hydrocarbons (TPHs) from crude oil. Following 16/18S rDNA sequence analysis, soil microorganisms efficient in the removal of TPHs were identified as Bacillus cereus, Bacillus thuringiensis, Geomyces pannorum, and Geomyces sp. A mixed culture of the above two isolates of bacteria and two of fungi were tested for its ability to remove TPHs from crude oil in solid phase (SOP) or slurry phase (SLP) of soil. The capability of the mixed culture in removing TPHs after 30 d incubation was higher in SLP than in SOP. Results of ecotoxicity studies using Artemia salina corroborated with those of TPHs removal from crude oil in SOP and SLP by the mixed culture of the selected bacteria and fungi.