@article{mbs:/content/journal/micro/10.1099/00221287-140-6-1433, author = "Curragh, Helen and Flynn, Orla and Larkin, Michael J. and Stafford, Thomas M. and Hamilton, John T. G and Harper, David B.", title = "Haloalkane degradation and assimilation by Rhodococcus rhodochrous NCIMB 13064", journal= "Microbiology", year = "1994", volume = "140", number = "6", pages = "1433-1442", doi = "https://doi.org/10.1099/00221287-140-6-1433", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-140-6-1433", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "chlorofatty acids", keywords = "lipid composition", keywords = "degradation", keywords = "Rhodococcus rhodcbrous", keywords = "haloalkanes", abstract = "The bacterium Rhodococcus rhodochrous NCIMB 13064, isolated from an industrial site, could use a wide range of 1-haloalkanes as sole carbon source but apparently utilized several different mechanisms simultaneously for assimilation of substrate. Catabolism of 1-chlorobutane occurred mainly by attack at the C-1 atom by a hydrolytic dehalogenase with the formation of butanol which was metabolized via butyric acid. The detection of small amounts of γ-butyrolactone in the medium suggested that some oxygenase attack at C-4 also occurred, leading to the formation of 4-chlorobutyric acid which subsequently lactonized chemically to γ-butyrolactone. Although 1-chlorobutane-grown cells exhibited little dehalogenase activity on 1-chloroalkanes with chain lengths above C10, the organism utilized such compounds as growth substrates with the release of chloride. Concomitantly, γ-butyrolactone accumulated to 1 mM in the culture medium with 1-chlorohexadecane as substrate. Traces of 4-hydroxybutyric acid were also detected. It is suggested that attack on the long-chain chloroalkane is initiated by an oxygenase at the non-halogenated end of the molecule leading to the formation of an Ω-chlorofatty acid. This is degraded by β-oxidation to 4-chlorobutyric acid which is chemically lactonized to γ-butyrolactone which is only slowly further catabolized via 4-hydroxybutyric acid and succinic acid. However, release of chloride into the medium during growth on long-chain chloroalkanes was insufficient to account for all the halogen present in the substrate. Analysis of the fatty acid composition of 1-chlorohexadecane-grown cells indicated that chlorofatty acids comprised 75% of the total fatty acid content with C14:0, C16:0, C16:1 and C18:1 acids predominating. Thus the incorporation of 16-chlorohexadecanoic acid, the product of oxygenase attack directly into cellular lipid represents a third route of chloroalkane assimilation. This pathway accounts at least in part for the incomplete mineralization of long-chain chloroalkane substrates. This is the first report of the coexistence of a dehalogenase and the ability to incorporate long-chain haloalkanes into the lipid fraction within a single organism and raises important questions regarding the biological treatment of haloalkane containing effluents.", }