Microbial Degradation of the Multiply Branched Alkane 2,6,10,15,19,23-Hexamethyltetracosane (Squalane) by Mycobacterium fortuitum and Mycobacterium ratisbonense

Abstract

Among several bacterial species belonging to the general Gordonia, Mycobacterium, Micromonospora, Pseudomonas, and Rhodococcus, only two mycobacterial isolates, Mycobacterium fortuitum strain NF4 and the new isolate Mycobacterium ratisbonense strain SD4, which was isolated from a sewage treatment plant, were capable of utilizing the multiply branched hydrocarbon squalane (2,6,10,15,19,23-hexamethyltetracosane) and its analogous unsaturated hydrocarbon squalene as the sole carbon source for growth. Detailed degradation studies and high-pressure liquid chromatography analysis showed a clear decrease of the concentrations of squalane and squalene during biomass increase. These results were supported by resting-cell experiments using strain SD4 and squalane or squalene as the substrate. The degradation of acyclic isoprenoids and alkanes as well as of acids derived from these compounds was also investigated. Inhibition of squalane and squalene degradation by acrylic acid indicated the possible involvement of ␤-oxidation in the degradation route. To our knowledge, this is the first report demonstrating the biodegradation of squalane by using defined axenic cultures.

Involvement of Two Latex-Clearing Proteins during Rubber Degradation and Insights into the Subsequent Degradation Pathway Revealed by the Genome Sequence of Gordonia polyisoprenivorans Strain VH2

“…The resulting organic acids are most likely metabolized via ␤-oxidation for several reasons: (i) the occurrence of intermediates identified during rubber degradation by S. coelicolor A1 are explainable through degradation via ␤-oxidation; (ii) inhibition by acrylic acid, a ␤-oxidation-specific inhibitor, was observed in strain A1 (18) and other rubber-degrading strains (72); and (iii) ␤-oxidation is also involved in microbial degradation of branched-chain alkanes, such as isooctane (84), pristane (62), phytane (83), squalane, and squalene. The latter is also known to be metabolized by strain VH2 (14). In our proposed rubber degradation pathway, an acyl-CoA synthetase converts the acid to an acyl-CoA thioester (Fig.…”

Acyltransferases in Bacteria

“…ates of incomplete isoprenoid catabolism (82,83). Isoprenoid WE biosynthesis from bulky substrates again demonstrates the broad substrate spectrum of AtfA-like acyltransferases and emphasizes that the type of accumulated lipids depends mainly on the physiological background and on available metabolites rather than on a restricted substrate range of the involved enzymes (83).…”

Application of Chemically Accelerated Biotreatment to Reduce Risk in Oil-Impacted Soils

“…PAHs (Kelley and Cerniglia 1995;Schneider et al, 1996) and highly branched aliphatic hydrocarbons (Berekaa and Steinbüchel 2000;Solano-Serena et al, 2000). This paper presents an initial characterization of a newly-isolated strain (GTI-23) of Mycobacterium austroafricanum, which is capable of growth on, and/or degradation of, various PAHs (with up to 5 fused rings), as well as straight-chain aliphatic hydrocarbons (decane, dodecane, and hexadecane).…”