Extracellular lipids produced by different Rhodococcus species

VILLALBA MS; ALVAREZ, HÉCTOR M

PUERTO MADRYN

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

SAIB

Rhodococcus bacteria accumulate variable amounts of triglycerides (TAG) during cultivation on diverse substrates. The intracellular TAG accumulation by rhodococci is a well established feature, but the extracellular export of TAG remains to be investigated. In this study we analyzed the ability of Rhodococcus species, such as R.opacus, R.jostii, R.wratislaviensis, R.ruber, R.erythropolis and R.fascians, to produce extracellular TAG. All studied strains were able to export TAG into the culture medium, and in proportion, those species with lower content of intracellular TAG, produced higher amounts of extracellular TAG. Interestingly, intracellular and extracellular TAG produced by all studied species exhibited different fatty acid (FA) composition as revealed by preparative thin layer and gas chromatography analyses. Monounsaturated FA occurred predominantly in intracellular TAG, whereas extracellular TAG contained almost exclusively saturated FA (86.5-100 % of total FA). Extracellular TAG from all rhodococcal species were composed predominantly by C16:0 and C18:0 (76-93 %), while C18:1 was one of the major FA in intracellular TAG. The presence of TAG with different FA composition inside and outside the cells suggests the occurrence of an export mechanism for lipids in rhodococci which probably involve export proteins.