Energy Reserves in Acinetobacter

Fixter, L. M.; Sherwani, Misbah-ul-Islam Khan

doi:10.1007/978-1-4899-3553-3_19

Cited by 11 publications

(6 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, an acyl-CoA (acyl-ACP) fatty alcohol transferase condenses the fatty alcohol with either acyl-ACP or acyl-CoA to give the final wax ester product. The first two steps of this pathway are indirectly supported by biochemical evidence gathered from studies of the metabolism of alkanes by Acinetobacter species and from studying wax ester biosynthesis in other microorganisms (10).…”

mentioning

confidence: 92%

Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase

1997

View full text Add to dashboard Cite

Acinetobacter calcoaceticus BD413 accumulates wax esters and triacylglycerol under conditions of mineral nutrient limitation. Nitrosoguanidine-induced mutants of strain BD413 were isolated that failed to accumulate wax esters under nitrogen-limited growth conditions. One of the mutants, Wow15 (without wax), accumulated wax when grown in the presence of cis-11-hexadecenal and hexadecanol but not hexadecane or hexadecanoic acid. This suggested that the mutation may have inactivated a gene encoding either an acyl-acyl carrier protein or acyl-coenzyme A (CoA) reductase. The Wow15 mutant was complemented with a cosmid genomic library prepared from wild-type A. calcoaceticus BD413. The complementary region was localized to a single gene (acr1) encoding a protein of 32,468 Da that is 44% identical over a region of 264 amino acids to a product of unknown function encoded by an open reading frame associated with mycolic acid synthesis in Mycobacterium tuberculosis H37Ra. Extracts of Escherichia coli cells expressing the acr1 gene catalyzed the reduction of acyl-CoA to the corresponding fatty aldehyde, indicating that the gene encodes a novel fatty acyl-CoA reductase.Wax esters are utilized in diverse biological roles. Prominent uses include coating the surfaces of plant leaves as epicuticular waxes to provide desiccation tolerance and protection against ultraviolet light and serving as carbon storage inclusions in some bacterial species such as Acinetobacter calcoaceticus. Wax esters also have industrial applications, serving as high-temperature lubricants, surface coatings, and emulsifying agents.The chemical structures of wax esters produced by A. calcoaceticus are similar to those found in other organisms such as jojoba (Simmondsia chinensis L.), a plant species native to the southwest region of the United States that is used for commercial wax ester production, and the sperm whale, the commercial source of wax esters prior to the worldwide ban on whaling (7). The proposed pathway for wax ester biosynthesis in A. calcoaceticus is illustrated in Fig. 1. In this pathway, three enzymes are directly involved in the conversion of acyl-acyl carrier protein (ACP), or acyl-coenzyme A (CoA), to wax esters. In the first step, acyl-CoA (or acyl-ACP) is reduced by an acyl-CoA (or acyl-ACP) reductase to its corresponding fatty aldehyde. This fatty aldehyde is then further reduced to its corresponding fatty alcohol by a fatty aldehyde reductase. Finally, an acyl-CoA (acyl-ACP) fatty alcohol transferase condenses the fatty alcohol with either acyl-ACP or acyl-CoA to give the final wax ester product. The first two steps of this pathway are indirectly supported by biochemical evidence gathered from studies of the metabolism of alkanes by Acinetobacter species and from studying wax ester biosynthesis in other microorganisms (10).Several previous studies have reported that fatty alcohol and fatty aldehyde dehydrogenases exist in various Acinetobacter species (6,11,24,25). These observations have been the result of investigations into th...

show abstract

mentioning

confidence: 92%

Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase

1997

View full text Add to dashboard Cite

show abstract

“…The accumulation of TAGs in large quantities has so far been described only for certain gram-positive bacteria of the actinomycetes group, belonging to the genera Mycobacterium, Nocardia, Rhodococcus, and Streptomyces (2). In contrast, WEs (oxoesters of long-chain primary fatty alcohols and long-chain fatty acids), along with small amounts of TAGs, seem to be common storage lipids within the gram-negative genus Acinetobacter (12,13,14,22). Recently, the key enzyme for storage lipid biosynthesis in Acinetobacter baylyi strain ADP1 (formerly Acinetobacter sp.…”

mentioning

confidence: 99%

Analysis of Storage Lipid Accumulation in Alcanivorax borkumensis : Evidence for Alternative Triacylglycerol Biosynthesis Routes in Bacteria

et al. 2007

View full text Add to dashboard Cite

Marine hydrocarbonoclastic bacteria, like Alcanivorax borkumensis, play a globally important role in bioremediation of petroleum oil contamination in marine ecosystems. Accumulation of storage lipids, serving as endogenous carbon and energy sources during starvation periods, might be a potential adaptation mechanism for coping with nutrient limitation, which is a frequent stress factor challenging those bacteria in their natural marine habitats. Here we report on the analysis of storage lipid biosynthesis in A. borkumensis strain SK2. Triacylglycerols (TAGs) and wax esters (WEs), but not poly(hydroxyalkanoic acids), are the principal storage lipids present in this and other hydrocarbonoclastic bacterial species. Although so far assumed to be a characteristic restricted to gram-positive actinomycetes, substantial accumulation of TAGs corresponding to a fatty acid content of more than 23% of the cellular dry weight is the first characteristic of large-scale de novo TAG biosynthesis in a gram-negative bacterium. The acyltransferase AtfA1 (ABO_2742) exhibiting wax ester synthase/acyl-coenzyme A:diacylglycerol acyltransferase (WS/DGAT) activity plays a key role in both TAG and WE biosynthesis, whereas AtfA2 (ABO_1804) was dispensable for storage lipid formation. However, reduced but still substantial residual TAG levels in atfA1 and atfA2 knockout mutants compellingly indicate the existence of a yet unknown WS/DGAT-independent alternative TAG biosynthesis route. Storage lipids of A. borkumensis were enriched in saturated fatty acids and accumulated as insoluble intracytoplasmic inclusions exhibiting great structural variety. Storage lipid accumulation provided only a slight growth advantage during short-term starvation periods but was not required for maintaining viability and long-term persistence during extended starvation phases.

show abstract

“…However, wax ester seems to be a common storage lipid within the genus Acinetobacter (6,7,8,11). The wax esters produced by Acinetobacter species comprise C 30 to C 36 wax esters composed of saturated and monounsaturated fatty acid and fatty alcohol moieties (6,8).…”

mentioning

confidence: 99%

Neutral Lipid Biosynthesis in Engineered Escherichia coli : Jojoba Oil-Like Wax Esters and Fatty Acid Butyl Esters

Kalscheuer

Stöveken

Luftmann

et al. 2006

Appl Environ Microbiol

113

View full text Add to dashboard Cite

Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.

show abstract

Energy Reserves in Acinetobacter

Cited by 11 publications

References 66 publications

Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase

Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase

Analysis of Storage Lipid Accumulation in Alcanivorax borkumensis : Evidence for Alternative Triacylglycerol Biosynthesis Routes in Bacteria

Neutral Lipid Biosynthesis in Engineered Escherichia coli : Jojoba Oil-Like Wax Esters and Fatty Acid Butyl Esters

Contact Info

Product

Resources

About