Aerobic and anaerobic metabolism of squalene by a denitrifying bacterium isolated from marine sediment

Rontani, Jean‐François; Mouzdahir, Abdelkrim; Michotey, Valérie; Bonin, Patricia

doi:10.1007/s00203-002-0457-8

Cited by 46 publications

(42 citation statements)

References 19 publications

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“…The differences in substrate selectivities and activities seen in the isoprenoid WSs described here, reported from Acinetobacter baylyi ADP1 (11,23,25), and more recently reported from Alcanivorax borkumensis (12) may reflect adaptations to available carbon sources in their respective environments (15)(16)(17). Identification of additional microbial WE biosynthetic genes will likely yield enzymes with new and interesting substrate selectivities.…”

Section: Discussionsupporting

confidence: 56%

“…To determine the substrate specificities and to test whether any of the cloned putative acyl-CoA synthetases can catalyze CoAactivation of isoprenoid acids, purified recombinant enzymes (Acs1, -2, -3, and -4) were assayed with various saturated fatty acid substrates containing different acyl chain lengths (C 10 , C 12 , C 14 , C 16 , C 18 , and C 20 ) and with the isoprenoid phytanic acid. HPLC analysis of the reaction products confirmed Acs1 to be a medium-chain acyl-CoA synthetase that accepts fatty acids with chain lengths ranging from C 10 to C 16 , while Acs2, -3, and -4 were found to be long-chain acyl-CoA synthetases that act on fatty acids with chain lengths ranging from C 12 to C 20 (data not shown). The long-chain acyl-CoA synthetases (Acs2, -3, and -4) showed the most activity when palmitic acid (C 16 ) was the substrate.…”

Section: Vol 189 2007 Wax Ester Biosynthesis In M Hydrocarbonoclasmentioning

confidence: 98%

“…HPLC analysis of the reaction products confirmed Acs1 to be a medium-chain acyl-CoA synthetase that accepts fatty acids with chain lengths ranging from C 10 to C 16 , while Acs2, -3, and -4 were found to be long-chain acyl-CoA synthetases that act on fatty acids with chain lengths ranging from C 12 to C 20 (data not shown). The long-chain acyl-CoA synthetases (Acs2, -3, and -4) showed the most activity when palmitic acid (C 16 ) was the substrate. Only Acs2 converted phytanic acid into phytanoyl-CoA, a finding confirmed by LC-MS (Fig.…”

Section: Vol 189 2007 Wax Ester Biosynthesis In M Hydrocarbonoclasmentioning

confidence: 98%

“…Another class of WEs is the isoprenoid WEs that are made from branched, long-chained isoprenoyl alcohol and isoprene fatty acid substrates. Isoprenoid WEs have been identified as a way to provide energy storage in Marinobacter species (15)(16)(17). Marinobacter species grow in marine sediment materials where there is an abundance of recalcitrant acyclic isoprenoid alcohols such as farnesol and phytol, which are derived from (bacterio)chlorophyll molecules (16,17).…”

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Biosynthesis of Isoprenoid Wax Ester inMarinobacter hydrocarbonoclasticusDSM 8798: Identification and Characterization of Isoprenoid Coenzyme A Synthetase and Wax Ester Synthases

2007

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Marinobacter hydrocarbonoclasticus DSM 8798 has been reported to synthesize isoprenoid wax ester storage compounds when grown on phytol as the sole carbon source under limiting nitrogen and/or phosphorous conditions. We hypothesized that isoprenoid wax ester synthesis involves (i) activation of an isoprenoid fatty acid by a coenzyme A (CoA) synthetase and (ii) ester bond formation between an isoprenoid alcohol and isoprenoyl-CoA catalyzed, most likely, by an isoprenoid wax ester synthase similar to an acyl wax ester synthase, wax ester synthase/diacylglycerol acyltransferase (WS/DGAT), recently described from Acinetobacter sp. strain ADP1. We used the recently released rough draft genome sequence of a closely related strain, M. aquaeolei VT8, to search for WS/DGAT and acyl-CoA synthetase candidate genes. The sequence information from putative WS/DGAT and acyl-CoA synthetase genes identified in this strain was used to clone homologues from the isoprenoid wax ester synthesizing Marinobacter strain. The activities of the recombinant enzymes were characterized, and two new isoprenoid wax ester synthases capable of synthesizing isoprenoid ester and acyl/isoprenoid hybrid ester in vitro were identified along with an isoprenoid-specific CoA synthetase. One of the Marinobacter wax ester synthases displays several orders of magnitude higher activity toward acyl substrates than any previously characterized acyl-WS and may reflect adaptations to available carbon sources in their environments.

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Section: Discussionsupporting

confidence: 56%

Section: Vol 189 2007 Wax Ester Biosynthesis In M Hydrocarbonoclasmentioning

confidence: 98%

Section: Vol 189 2007 Wax Ester Biosynthesis In M Hydrocarbonoclasmentioning

confidence: 98%

mentioning

confidence: 99%

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Biosynthesis of Isoprenoid Wax Ester inMarinobacter hydrocarbonoclasticusDSM 8798: Identification and Characterization of Isoprenoid Coenzyme A Synthetase and Wax Ester Synthases

2007

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“…Briefly, the suspensions were repeatedly frozen and thawed and were subsequently incubated in the presence of sodium dodecyl sulfate and proteinase K. DNA was extracted by applying CTAB (hexadecyl-methylammonium bromide), phenol, chloroform, and isoamyl alcohol and was precipitated by the addition of isopropanol. The 16S rRNA gene of the strain was amplified by PCR with universal primers for eubacteria-EU3 and EU5-as previously described (32). The nucleotide sequence of the PCR product was determined by MWG Biotech Company (Ebersberg, Germany).…”

Section: Methodsmentioning

confidence: 99%

Production of a Polyunsaturated Isoprenoid Wax Ester during Aerobic Metabolism of Squalene by Marinobacter squalenivorans sp. nov

Rontani¹,

Mouzdahir

Michotey³

et al. 2003

Appl Environ Microbiol

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This paper describes the production of 5,9,13-trimethyltetradeca-4E,8E,12-trienyl-5,9,13-trimethyltetradeca-4E,8E,12-trienoate during the aerobic degradation of squalene by a Marinobacter strain, 2Asq64, isolated from the marine environment. A pathway involving initial cleavage of the C 10 -C 11 or C 14 -C 15 double bonds of the squalene molecule is proposed to explain the formation of this polyunsaturated isoprenoid wax ester. The isoprenoid wax ester content reached 1.1% of the degraded squalene at the mid-exponential growth phase and then decreased during the stationary phase. The wax ester content increased by approximately threefold in N-limited cultures, in which the ammonium concentration corresponds to conditions often found in marine sediments. This suggests that the bacterial formation of isoprenoid wax esters might be favored in such environments. The bacterial strain is then characterized as a member of a new species, for which we propose the name Marinobacter squalenivorans sp. nov.The microbial communities of marine environments are often exposed to fluctuating conditions such as the availability of nutrients. Microorganisms have developed a variety of strategies that allow them to survive in these variable environments; the accumulation of storage lipids is only one of them (4). Storage compounds occur normally as intracellular inclusions in bacteria (42). While the accumulation of triacylglycerols occurs preferentially in eukaryotic organisms, triacylglycerols are not frequently found as storage compounds in bacteria (4). Bacteria usually accumulate specialized lipids such as poly(3-hydroxybutyric acid) or other polyhydroxyalkanoic acids (31,44,45). Only some bacteria of the genera Mycobacterium (6), Streptomyces (29), and Rhodococcus (3, 5, 50) accumulate triacylglycerols. Wax esters, which are trace constituents of numerous bacteria (e.g., Escherichia coli [28], Serratia marcescens, Bacillus cereus [22], Nocardia sp. [21], and Thiobacillus thioparus [15]), are generally considered as widespread energy storage components in the genus Acinetobacter (18). In fact, it was previously demonstrated that different strains of A. calcoaceticus increased their wax ester contents in N-limited cultures and that the accumulated wax esters were degraded to water-soluble molecules and CO 2 during C starvation (18). These results showed that these compounds may serve as an ATP-generating substrate during starvation.We previously observed the production of several isoprenoid wax esters during the aerobic degradation of 6,10,14-trimethylpentadecan-2-one and phytol by four bacteria (Acinetobacter sp. strain PHY9, Pseudomonas nautica [IP85/617], Marinobacter sp. strain CAB [DSMZ11874], and Marinobacter hydrocarbonoclasticus [ATCC49840]) isolated from the marine environment (33). The amount of these esters increased considerably in N-limited cultures, in which the ammonium concentration corresponds to conditions often found in marine sediments. Similar isoprenoid wax esters have also been detected during the degrada...

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Harnessing a methane‐fueled, sediment‐free mixed microbial community for utilization of distributed sources of natural gas

Marlow¹,

Kumar²,

Enalls³

et al. 2018

Biotech & Bioengineering

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Harnessing the metabolic potential of uncultured microbial communities is a compelling opportunity for the biotechnology industry, an approach that would vastly expand the portfolio of usable feedstocks. Methane is particularly promising because it is abundant and energy‐rich, yet the most efficient methane‐activating metabolic pathways involve mixed communities of anaerobic methanotrophic archaea and sulfate reducing bacteria. These communities oxidize methane at high catabolic efficiency and produce chemically reduced by‐products at a comparable rate and in near‐stoichiometric proportion to methane consumption. These reduced compounds can be used for feedstock and downstream chemical production, and at the production rates observed in situ they are an appealing, cost‐effective prospect. Notably, the microbial constituents responsible for this bioconversion are most prominent in select deep‐sea sediments, and while they can be kept active at surface pressures, they have not yet been cultured in the lab. In an industrial capacity, deep‐sea sediments could be periodically recovered and replenished, but the associated technical challenges and substantial costs make this an untenable approach for full‐scale operations. In this study, we present a novel method for incorporating methanotrophic communities into bioindustrial processes through abstraction onto low mass, easily transportable carbon cloth artificial substrates. Using Gulf of Mexico methane seep sediment as inoculum, optimal physicochemical parameters were established for methane‐oxidizing, sulfide‐generating mesocosm incubations. Metabolic activity required >∼40% seawater salinity, peaking at 100% salinity and 35 °C. Microbial communities were successfully transferred to a carbon cloth substrate, and rates of methane‐dependent sulfide production increased more than threefold per unit volume. Phylogenetic analyses indicated that carbon cloth‐based communities were substantially streamlined and were dominated by Desulfotomaculum geothermicum. Fluorescence in situ hybridization microscopy with carbon cloth fibers revealed a novel spatial arrangement of anaerobic methanotrophs and sulfate reducing bacteria suggestive of an electronic coupling enabled by the artificial substrate. This system: 1) enables a more targeted manipulation of methane‐activating microbial communities using a low‐mass and sediment‐free substrate; 2) holds promise for the simultaneous consumption of a strong greenhouse gas and the generation of usable downstream products; and 3) furthers the broader adoption of uncultured, mixed microbial communities for biotechnological use.

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Aerobic and anaerobic metabolism of squalene by a denitrifying bacterium isolated from marine sediment

Cited by 46 publications

References 19 publications

Biosynthesis of Isoprenoid Wax Ester inMarinobacter hydrocarbonoclasticusDSM 8798: Identification and Characterization of Isoprenoid Coenzyme A Synthetase and Wax Ester Synthases

Biosynthesis of Isoprenoid Wax Ester inMarinobacter hydrocarbonoclasticusDSM 8798: Identification and Characterization of Isoprenoid Coenzyme A Synthetase and Wax Ester Synthases

Production of a Polyunsaturated Isoprenoid Wax Ester during Aerobic Metabolism of Squalene by Marinobacter squalenivorans sp. nov

Harnessing a methane‐fueled, sediment‐free mixed microbial community for utilization of distributed sources of natural gas

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