Examinando por Autor "Rodríguez Mateus, Zully"

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  • Publicación
    Acceso abierto
    Isolation and Molecular characterization of microorganisms with potential for the degradation of oil and grease from palm oil refinery wastes
    (2016-04) Rodríguez Mateus, Zully; Agualimpia Valderrama, Bayron-Enrique; Zafra, German; Derechos Reservados - Chemical Engineering Transactions, 2016
    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.
  • Publicación
    Acceso abierto
    Molecular detection and characterization of novel lipase genes of the lipolytic yeast Candida palmioleophila
    (2018-05-01) Rodríguez Mateus, Zully; Vera Pacheco, Katerine; Zafra, German
    In this study we analyzed the genetic variability of lipase gene sequences from eight oil and grease-degrading strains of Candida palmioleophila and to relate it to their degrading ability. The genetic variability of lipase genes was analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP) and low-stringency single specific primer- PCR (LSSP-PCR), in order to obtain specific DNA fingerprints from each strain, which were subsequently compared by bioinformatic programs. DNA fingerprints were contrasted to the ability of each strain to remove palm oil in liquid culture. The results showed that at least three genes encoding lipases are present in C. palmioleophila, two of them resembling the LIP2 and LIP6 genes of C. albicans. DNA fingerprints obtained by LSSP-PCR revealed differences in the sequences of C. palmioleophila lipase genes, which allowed to group the strains according to their degrading activity. C. palmioleophila strains SACL05, SACL08 and SACL11, which showed the highest removal of palm oil after 72 h (77 to 79 % removal), were grouped in a single clade in dendrograms. Similarly, strains SACL01, SACL03, SACL06 and SACL09, which showed intermediate removal activity of palm oil (54 to 76%) grouped in a different clade. This suggests the genetic variability in lipase genes is directly related to the differences found in the efficiency of degradation of oils. On the other hand, DNA fingerprints obtained by PCR-RFLP did not allow to differentiate the strains and did not generate changes in the bands patterns between the analyzed strains. In conclusion, this study reported for the first time the detection and characterization of lipase genes from the lipolytic yeast Candida palmioleophila, and their association to the degradation of oils.