Degradation pathways of cyclic alkanes in Rhodococcus sp. NDKK48

Abstract

The degradation pathways for cyclic alkanes (c-alkanes) in Rhodococcus sp. NDKK48 were investigated. Strain NDKK48 used dodecylcyclohexane as a sole carbon and energy source, and five metabolites in the dodecylcyclohexane degradation pathway were detected by gas-chromatography/mass spectra. The metabolites were identified as cyclohexanecarboxylic acid, cyclohexylacetic acid, 1-cyclohexene-1-acetic acid, 4-dodecylcyclohexanol, and 4-dodecylcyclohexanone. The strain degrades dodecylcyclohexane via a ring oxidation pathway and an alkyl side chain oxidation pathway. Cyclohexanecarboxylic acid was further oxidized to muconic acid via 1-cyclohexene-1-carboxylic acid and benzoic acid, and the muconic acid was finally used by strain NDKK48 for growth. Methylcyclohexane and cyclohexane were co-oxidized with hexadecane by strain NDKK48. Methylcyclohexane was degraded via a ring oxidation pathway, and the degradation pathway contained part of the Baeyer-Villiger oxidation for ring cleavage. Cyclohexane was also degraded by the same pathway as methylcyclohexane. Thus, strain NDKK48 has two pathways for the complete degradation of c-alkanes.

Phylogenetic analysis of long-chain hydrocarbon-degrading bacteria and evaluation of their hydrocarbon-degradation by the 2,6-DCPIP assay

“…This strain did degrade c-alkanes under limited conditions, such as co-metabolism with n-alkanes (Koma et al 2003a). On the other hand, strains NDKK48 and NDKY76A used n-alkanes and c-alkanes as sole carbon and energy sources (Koma et al 2003b), but the metabolic pathways for c-alkanes differed between the two strains (Koma et al 2003a(Koma et al , 2005. Since the hydrocarbon-degrading abilities seem to differ among genera, exhaustive analyses of hydrocarbon-degradation will be important for selecting microorganisms for bioremediation of hydrocarbons.…”

Novel biodegradation pathways of cyclohexane by Rhodococcus sp. EC1

“…the aromatization; THF to furan via 2,3-hydrofuran and lactone formation, ring-cleavage of THF via tetrahydrofuran-2-ol and gamma-butyrolactione [13]. Previously aromatization of cyclic alkanes has been reported in limited number of studies; by aerobic bacteria [7], by denitrifying bacteria [6], and by animal liver cells [14].…”

“…Generally, aromatization plays an important role in the biosynthesis of aromatic amino acids and lignin and estrogen. Although the involvement of aromatization in biodegradation is uncommon, in limited number of studies, biodegradation of cyclic alkanes have been reported by aromatization in aerobic bacteria [6]. Kaneda [7] also reported that Corynebacterium cyclohexanicum degraded cyclohexanecarboxylic acid through the aromatization.…”

Molecular Insight into Substrate Recognition and Catalysis of Baeyer–Villiger Monooxygenase MtmOIV, the Key Frame-Modifying Enzyme in the Biosynthesis of Anticancer Agent Mithramycin

“…(2) Additionally, BVMO’s are known to be responsible for pro-drug activation (3) as well as biodegradation reactions. (4-6)…”