Abstract
In this study we isolated and characterized native microorganisms with the ability to degrade oil and grease (O&G) and evaluated their potential for the treatment of POMEs from a palm oil refining process. Yeast and bacterial isolates were obtained from solid and liquid wastes from a grease trap of a palm oil refining process, based on their ability to use palm oil as sole carbon source in solid medium. Molecular identification of microorganisms was performed by PCR techniques, revealing that isolates corresponded to Candida and Bacillus species, with a high degree of similarity with reported O&G-degrading organisms. Five out of these isolates showed lipolytic activity evidenced by changes in the turbidity, colour and produced a substantial decrease in O&G concentrations in liquid MBS cultures containing palm oil. These isolates promoted the highest O&G decrease in POME samples with 56 %, 77 %, 78 %, 76 % and 79 % O&G removal after 72 hours respectively. A microbial consortia composed of five degrading yeasts produced a O&G reduction up to 84 % in POME samples after 48 hours, evidencing a synergic effect of the microorganisms. The results of this study showed that bioaugmentation of polluted wastewaters from palm oil extraction with native microorganisms isolated from oily residues can be efficiently used to greatly improve the removal of grease, oils and organic matter.
