Accumulation of storage lipids in species of Rhodococcus and Nocardia and effect of inhibitors and polyethylene glycol

Abstract

Members of the genera Rhodococcus and Nocardia corallina were investigated for their capability to accumulate storage lipids that occur in the cytoplasm during cultivation of the cells under nitrogen-limiting conditions in the absence or presence of various effectors. All bacteria were able to accumulate triacylglycerols (TAG) as main compounds plus minor amounts of diacylglycerols and wax esters. In addition to neutral lipids, R. fascians, R. erythropolis, and R. opacus MR22 accumulated small amounts of polyhydroxybutyrate (PHB), and N. corallina and R. ruber accumulated significant amounts of polyhydroxyalkanoates (PHA) consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) from glucose or valerate. Alloxan or 3-nitropropionate, which are inhibitors of the citric acid cycle, caused a decrease in the content of odd-numbered fatty acids in the TAG accumulated from acetate by R. opacus PD630. Cerulenin, an inhibitor of the fatty acid de novo synthesis, completely inhibited accumulation of TAG from glucose or gluconate but not from hexadecane in all bacteria investigated. In addition, cerulenin caused an increase of the PHA content and resulted in an increase of the relative amounts of 3HB units in the PHA in R. ruber and N. corallina. Acrylic acid, an inhibitor of fatty acid P-oxidation, completely or partially inhibited accumulation of TAG from hexadecane or valerate, respectively, in R. opacus PD630. In R. ruber, acrylic acid completely inhibited accumulations of TAG from valerate; under these conditions the content of PHA increased twofold, and the polyester consisted exclusively of 3HV. PEG-200 (0.2 to 5%, w/v) caused a decrease in the PHA content, but stimulated the incorporation of 3HV units into the PHA in R. ruber. Therefore, the relative amounts and compositions of both storage lipids can be affected by various compounds in these Gram-positive bacteria. Anhliufung von Speicherlipiden in den GattungenRhodome cus und Nocardia und EinfluE von Inhibitoren und Polyethylenglykol. Vertreter der Gattungen Rhodococcus und Nocardia corallina wurden auf ihre Fahigkeit, Speicherlipide im Cytoplasma wahrend der Kultivierung unter stickstomimitierenden Bedingungen in Gegenwart oder Abwesenheit verschiedener Effektoren zu akkumulieren, untersucht. Alle untersuchten Bakterien akkumulierten Triglyceride (TG) als Hauptkomponente sowie als Nebenkomponenten zusatzlich Diglyceride und Wachsester. R. fascians, R. etythropolis und R. opacus MR22 akkumulierten dariiber hinaus geringe Mengen Poly(3-Hydroxybutte~ure), (PHB) wiihrend N. corallina und R. ruber dariiber hinaus betrachtliche Mengen Polyhydroxyalkanoate (PHA)bestehend aus 3-Hydroxybuttersaure (3HB) und 3-Hydroxyvaleriansaure (3HV) ausgehend von Glucose oder Valeriansaure akkumulierten. Alloxan und 3-Nitropropionsaure, Inhibitoren des Zitronensaurezyklus, bewirkten eine Abnahme des Gehalts von Fettsauren mit ungerader Anzahl von C-Atomen in den TG in Acetatzellen von R. opacus PD630. Cerulenin, ein Hemmstoff der Fettsauresynthese, unterdriickte die Akkumulati...

Evaluation of the biocompatibile ionic liquid 1-methyl-3-methylimidazolium dimethylphosphite pretreatment of corn cob for improved saccharification

“…Our data suggest that the hydrolyzates (from pretreatment/saccharification process or enzymatic in situ hydrolysis process) posed no negative effect on R. opacus ACCC41043 growth and lipid production. It was reported that R. opacus can accumulate lipid up to 20-76% of the CDM in nitrogen-limited medium (Alvarez et al 1997;Steinbüchel 2001), while our data suggested that the R. opacus strain ACCC41043 could accumulate 41-43% lipid of CDM using simple mineral salt medium with hydrolyzates as carbon source.…”

“…It was reported by Alvarez and coworkers that the C16 and C18 distribution in R. opacus MR22 are 34.8 and 39.3 mol%, respectively (Alvarez et al 1997). The composition of C18 in R. opacus ACCC41043 was similar to that of C18 in R. opacus MR22.…”

Novel Iso-branched Ether Lipids as Specific Markers of Developmental Sporulation in the Myxobacterium Myxococcus xanthus

“…in the dogfish Squalus acanthias) (62). Triglycerides in general are well known storage compounds of carbon and energy, which are used by several eukaryotes like mammals and plants (12), but have only rarely been found in prokaryotes, which in some cases seem to use polyhydroxyalkanoates instead (63)(64)(65)(66)(67)(68).…”

PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

“…Similarly, additions to cultivations of A. vinelandii UWD of 2% (w/v) of various PEGs from PEG-106 to PEG-3400 also resulted in variable polymer yields (Zanzig et al 2003). P(HB-co-HV) synthesis by R. ruber was influenced by the presence of 0.2-5% (w/v) PEG-200, with a reduction in scl-PHA yield of up to 50% (Alvarez et al 1997). Such variations in polymer yields are obviously due to the influence of PEGs on the bioprocessing systems.…”

“…Furthermore, this scl-PHA also contained approximately 3 mol % 3-hydroxyvalerate units, P(3HB-co-3HV-co-4HB), (Shi et al 1996a). Steinbüchel and coworkers have compared the influence of PEG-200 to a variety of chemical inhibitors of fatty acid oxidation and the citric acid cycle to probe the influence of such polyethers on lipid and PHA synthesis in various Rhodococcus and Nocardia species (Alvarez et al 1997). In this study they report that 0.2 to 5% (w/v) PEG-200 in the cultivation media caused decreases in scl-PHA contents in R. ruber, but under the conditions studied also stimulated greater incorporation of 3HV monomer units.…”