Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents

Abstract

Six aerobic alkanotrophs (organism that can metabolize alkanes as their sole carbon source) isolated from deep-sea hydrothermal vents were characterized using the radical clock substrate norcarane to determine the metalloenzyme and reaction mechanism used to oxidize alkanes. The organisms studied were Alcanivorax sp. strains EPR7 and MAR14, Marinobacter sp. strain EPR21, Nocardioides sp. strains EPR26w, EPR28w, and Parvibaculum hydrocarbonoclasticum strain EPR92. Each organism was able to grow on n-alkanes as the sole carbon source and therefore must express genes encoding an alkane-oxidizing enzyme. Results from the oxidation of the radical-clock diagnostic substrate norcarane demonstrated that five of the six organisms (EPR7, MAR14, EPR21, EPR26w, and EPR28w) used an alkane hydroxylase functionally similar to AlkB to catalyze the oxidation of medium-chain alkanes, while the sixth organism (EPR92) used an alkane-oxidizing cytochrome P450 (CYP)-like protein to catalyze the oxidation. DNA sequencing indicated that EPR7 and EPR21 possess genes encoding AlkB proteins, while sequencing results from EPR92 confirmed the presence of a gene encoding CYP-like alkane hydroxylase, consistent with the results from the norcarane experiments.

Heterotrophic Proteobacteria in the vicinity of diffuse hydrothermal venting

“…Complex hydrocarbons of biotic or abiotic origin were detected and investigated in sulphide deposits of the Rainbow hydrothermal field (Lein et al ., ), and polycyclic organic compounds have been detected at other hydrothermally influenced sites (Simoneit and Fetzer, ; Geptner et al ., ). With this information in mind, vent vicinity characteristic taxa identified in this study, such as Thalassolituus , Alcanivorax , Acinetobacter, Hyphomonas and Sphingomonas are also often related to contaminated environments (Cavicchioli et al ., ; Lai et al ., ; Bertrand et al ., ; Fondi et al ., ). Some of these are known to be capable of xenobiotics degradation or even to grow best on alkanes (Weiner et al ., ; Yakimov et al ., ; Maeda et al ., ).…”

Survival and Energy Producing Strategies of Alkane Degraders Under Extreme Conditions and Their Biotechnological Potential

“…Other PCR-based study examining the Atlantic Ocean surface seawater revealed that both alkB and cyp153 genes coexist in Alcanivorax and Salinisphaera species, whereas all Parvibaculum species possess only cyp153 and discovered new culturable alkane-degraders belonging to Brachybacterium , Idiomarina , Leifsonia , Martelella , Kordiimonas , Parvibaculum , and Tistrella ( Wang W. et al, 2010 ; Supplementary Table S1 ). Characterization of culturable Alcanivorax strains, Marinobacter , Nocardioides , Parvibaculum strains, originating from deep-sea hydrothermal vents, also revealed that only Parvibaculum strain possesses an alkane-oxidizing cytochrome P450 (CYP)-like protein to degrade alkanes ( Bertrand et al, 2013 ). In subtropical seawater, alkB was detected in Gallaecimonas , Castellaniella , Paracoccus , and Leucobacter species, which shows a completely different bacterial community compared to the pelagic area ( Wang L. et al, 2010 ), indicating that the distribution of alkane degraders varies with ocean conditions and geographical location.…”

Characterization of Polyethylene Oxide and Sodium Alginate for Oil Contaminated-Sand Remediation

“…model, Fisher Scientific) for 24 h. Decane (Sigma-Aldrich, St. Louis, MO, USA, anhydrous, >99%, C 10 H 22 ) was employed to simulate the oil in oil-contaminated soils. Decane is a constituent of petroleum [46][47][48][49][50][51][52][53][54] and represents the petroleum contaminant in soils due to its interfacial properties, which affect fluid flow patterns in porous media [52][53][54]. Ottawa sands that have different particle size distributions were employed in this study (Figure 2).…”