This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Generation of Precursor Metabolites and Energy|
Note: This is an engineered pathway. It does not occur naturally in any known organism, and has been constructed in a living cell by metabolic engineering.
The enzymes catalyzing the steps of this pathway have been assembled from the following organisms : Acinetobacter sp. ADP1 [Kalscheuer06], Escherichia coli K-12 substr. MG1655 , Zymomonas mobilis [Kalscheuer06]
The synthesis of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) by transesterification of long chain fatty acids from plant oil triacylglycerols (TAGs) with methanol and ethanol, respectively, produces biodiesel that can be used as a petroleum-based diesel substitute [Kalscheuer06]. The use of biodiesel has many positive ecological aspects, however, there are numerous limitations and drawbacks to its production on a technical scale. These include:
1) Production depending on the availability of sufficient vegetable oil feedstock.
2) Vegetable oils used contain TAGs which cannot be used directly and have to be transesterified, this is cost intensive and energy consuming.
3) The production of FAMEs requires methanol which is currently produced from natural gas, thus FAME-based biodiesel is not truly a renewable product.
About this Pathway
This pathway for the biosynthesis of FAEEs was metabolically engineered in Escherichia coli [Kalscheuer06]. The Zymomonas mobilis pyruvate decarboxylase and alcohol dehydrogenase II enzymes were cloned to aerobically generate ethanol, and wax ester synthase/acyl-CoA diacylglycerol acyltransferase bifunctional enzyme (WS/DGAT) from Acinetobacter sp. ADP1 was cloned to transesterify the acyl moieties of fatty acyl-CoA thioesters in Escherichia coli [Kalscheuer06]. Cells were cultivated aerobically with glucose and oleic acid.
Catalanotti12: Catalanotti C, Dubini A, Subramanian V, Yang W, Magneschi L, Mus F, Seibert M, Posewitz MC, Grossman AR (2012). "Altered fermentative metabolism in Chlamydomonas reinhardtii mutants lacking pyruvate formate lyase and both pyruvate formate lyase and alcohol dehydrogenase." Plant Cell 24(2);692-707. PMID: 22353371
Chae11: Chae, Lee (2011). "The functional annotation of protein sequences was performed by the in-house Ensemble Enzyme Prediction Pipeline (E2P2, version 1.0). E2P2 systematically integrates results from three molecular function annotation algorithms using an ensemble classification scheme. For a given genome, all protein sequences are submitted as individual queries against the base-level annotation methods. The individual methods rely on homology transfer to annotate protein sequences, using single sequence (BLAST, E-value cutoff <= 1e-30, subset of SwissProt 15.3) and multiple sequence (Priam, November 2010; CatFam, version 2.0, 1% FDR profile library) models of enzymatic functions. The base-level predictions are then integrated into a final set of annotations using an average weighted integration algorithm, where the weight of each prediction from each individual method was determined via a 0.632 bootstrap process over 1000 rounds of testing. The training and testing data for E2P2 and the BLAST reference database were drawn from protein sequences with experimental support of existence, compiled from SwissProt release 15.3."
Dennis91: Dennis MW, Kolattukudy PE (1991). "Alkane biosynthesis by decarbonylation of aldehyde catalyzed by a microsomal preparation from Botryococcus braunii." Arch Biochem Biophys 287(2);268-75. PMID: 1898004
Dickinson00: Dickinson JR, Harrison SJ, Dickinson JA, Hewlins MJ (2000). "An investigation of the metabolism of isoleucine to active Amyl alcohol in Saccharomyces cerevisiae." J Biol Chem 275(15);10937-42. PMID: 10753893
Flikweert99: Flikweert MT, de Swaaf M, van Dijken JP, Pronk JT (1999). "Growth requirements of pyruvate-decarboxylase-negative Saccharomyces cerevisiae." FEMS Microbiol Lett 174(1);73-9. PMID: 10234824
Fulda02: Fulda M, Shockey J, Werber M, Wolter FP, Heinz E (2002). "Two long-chain acyl-CoA synthetases from Arabidopsis thaliana involved in peroxisomal fatty acid beta-oxidation." Plant J 32(1);93-103. PMID: 12366803
Hemschemeier08: Hemschemeier A, Jacobs J, Happe T (2008). "Biochemical and physiological characterization of the pyruvate formate-lyase Pfl1 of Chlamydomonas reinhardtii, a typically bacterial enzyme in a eukaryotic alga." Eukaryot Cell 7(3);518-26. PMID: 18245276
Ioki12: Ioki M, Baba M, Bidadi H, Suzuki I, Shiraiwa Y, Watanabe MM, Nakajima N (2012). "Modes of hydrocarbon oil biosynthesis revealed by comparative gene expression analysis for race A and race B strains of Botryococcus braunii." Bioresour Technol 109;271-6. PMID: 22257857
Kalscheuer03: Kalscheuer R, Steinbuchel A (2003). "A novel bifunctional wax ester synthase/acyl-CoA:diacylglycerol acyltransferase mediates wax ester and triacylglycerol biosynthesis in Acinetobacter calcoaceticus ADP1." J Biol Chem 278(10);8075-82. PMID: 12502715
KillenbergJabs96: Killenberg-Jabs M, Konig S, Hohmann S, Hubner G (1996). "Purification and characterisation of the pyruvate decarboxylase from a haploid strain of Saccharomyces cerevisiae." Biol Chem Hoppe Seyler 377(5);313-7. PMID: 8828822
Kondo97: Kondo K, Horinouchi S (1997). "Characterization of the genes encoding the three-component membrane-bound alcohol dehydrogenase from Gluconobacter suboxydans and their expression in Acetobacter pasteurianus." Appl Environ Microbiol 63(3);1131-8. PMID: 9055427
Lee85: Lee T.C., Langston-Unkefer P.J. "Pyruvate decarboxylase from Zea mays L. I. Purification and partial characterization from mature kernels and anaerobically treated roots." Plant Physiol. (1985) 79:242-247.
Lewin01: Lewin TM, Kim JH, Granger DA, Vance JE, Coleman RA (2001). "Acyl-CoA synthetase isoforms 1, 4, and 5 are present in different subcellular membranes in rat liver and can be inhibited independently." J Biol Chem 276(27);24674-9. PMID: 11319232
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