Utilization of glycerol by Rhodococcus species

HERRERO M; ALVAREZ, HÉCTOR M

PUERTO MADRYN

Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2010

SAIB

Biodiesel production from animal fats and vegetable oils generates glycerol as the main by-product. Glycerol can be used for oil and biofuel production by oleaginous bacteria, such as Rhodococcus bacteria. The ability of Rhodococcus strains to utilize glycerol, using physiological, bioinformatic and molecular methods, has been investigated. Strains belonging to R.jostii (6) R.opacus (2), R.ruber (1), R.fascians (2) and R.erythropolis (2) were used in this study. Most strains were able to grow on glycerol, with the exception of 4 R.jostii strains. The glpk gene (glycerol kinase) was amplified by PCR in these 4 strains, and their sequences were analyzed. We observed a deletion of the nucleotide 721 in the glpk of R.jostii strain 346, which may produce a frame shift in the sequence. Among the glycerol-grown strains, those belonging to R.opacus, R.jostii and R.ruber showed a large lag phase (app. 7 days) before growing; whereas R.fascians and R.erythropolis showed good growth. A genome-wide bioinformatic analysis of key genes of glycerol metabolism in R.erythropolis PR4 and SK121, R.opacus B4, R.jostii RHA1 and M.smegmatis showed the occurrence of gplF genes encoding a Glycerol Uptake Facilitator (GlpF) in R.erythropolis, and their absence in R.opacus and R.jostii genomes, which is in agreement with the growth profiles on glycerol observed. The results suggested differences in the genetic potential for glycerol metabolism among Rhodococcus species, and the eventual occurrence of mutations in key genes.