Repositorio Digital

Resumen en ingles

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.