TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The fatty ester production host is selected from a mammalian cell, plant cell, insect cell, yeast cell, fungus cell, filamentous fungi cell, bacterial cell, a Gram-positive bacteria, a Gram-negative bacteria, Escherichia, Bacillus, Lactobacillus, Rhodococcus, Pseudomonas, Aspergillus, Trichoderma, Neurospora, Fusarium, Humicola, Rhizomucor, Kluyveromyces, Pichia, Mucor, Myceliophtora, Penicillium, Phanerochaete, pleurotus, Trametes, Chrysosporium, Saccharomyces, Stenotrophamonas, Schizosaccharomyces, Yarrowia, Streptomyces, a Bacillus lentus cell, Bacillus brevis cell, Bacillus stearothermophilus cell, Bacillus licheniformis cell, Bacillus alkalophilus cell, Bacillus coagulans cell, Bacillus circulans cell, Bacillus pumilis cell, Bacillus thuringiensis cell, Bacillus clausii cell, Bacillus megaterium cell, Bacillus subtilis cell, Bacillus amyloliquefaciens cell, Trichoderma koningii cell, Trichoderma viride cell, Trichoderma reesei cell, Trichoderma longibrachiatum cell, Aspergillus awamori cell, Aspergillus fumigates cell, Aspergillus foetidus cell, Aspergillus nidulans cell, Aspergillus niger cell, Aspergillus oryzae cell, Humicola insolens cell, Humicola lanuginose cell, Rhodococcus opacus cell, Rhizomucor miehei cell, Mucor michei cell, Streptomyces lividans cell, Streptomyces murinus cell, Actinomycetes cell, a chinese hamster ovary (CHO) cell, COS cell, VERO cell, baby hamster kidney (BHK) cell, HeLa cell, a Cv1 cell, Madin-Darby Canine Kidney (MDCK) cell, 293 cell, 3T3 cell, PC12 cell, Escherichia coli cell, a strain B Escherichia coli cell, a strain C Escherichia coli cell, a strain K Escherichia coli cell, or a strain W Escherichia coli cell; a recombinant cell that lacks a nucleic acid sequence encoding an acyl-CoA dehydrogenase enzyme or where expression of an acyl-CoA dehydrogenase enzyme is attenuated in the recombinant cell (preferably a heterologous nucleic acid sequence encoding an ester synthase enzyme, heterologous nucleic acid sequence encoding a thioesterase enzyme, or heterologous nucleic acid sequence encoding an acyl-CoA synthase enzyme). The processing the alcohol production substrate is performed by an alcohol production host selected from at least one of Saccharomyces cerevisiae, Saccharomyces distaticus, Saccharomyces uvarum, Schizosaccharomyces pombe, Kluyveromyces marxianus, Kluyveromyces fragilis, Candida pseudotropicalis, Candida brassicae, Clostridium, Clostridium acetobutylicum, Clavispora lusitaniae, Clavispora opuntiae, Pachysolen tannophilus, Bretannomyces clausenii, Zymomonas mobilis, Zymomonas, Clostridium thermocellum, Klebsiella oxytoca, Bacillus subtillis, yeast, Sacchromyces, Thermatoga, Bacillus, Pseudomonas, Actinomycetes, Streptomyces, Escherichia, Kluyveromyces, Candida, Clavispora, Pichia, Schizosaccharomyces, Hansenula, Pachysolen or Bretannomyces (preferably yeast, especially Saccharomyces cerevisiae or a bacterium from a genus chosen from Zymomonas, Clostridium, or Escherichia, especially Escherichia coli).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the method, between processing the alcohol production substrate and providing the alcohol composition to the fatty ester production host, an alcohol concentration of the alcohol composition, as measured by volume, changes by no more than about 20%. The alcohol is less than about 20 (preferably 95)% by volume of the alcohol composition that is provided to the fatty ester production host. The processing the alcohol production substrate and processing the fatty ester production substrate are performed simultaneously. The processing the alcohol production substrate is performed in a first vessel and processing the fatty ester production substrate is performed in a second vessel, where the first vessel is in fluid communication with the second vessel. The processing the alcohol production substrate is performed by an alcohol production host. The processing the alcohol production substrate and processing the fatty ester production substrate are performed in a same vessel. Preferred System: The fatty ester production vessel comprises a fatty ester production host comprising a heterologous nucleic acid sequence encoding an enzyme selected from a thioesterase, an ester synthase, an alcohol acyltransferase, a fatty alcohol forming acyl-CoA (acyl coenzyme A) reductase, an acyl-CoA reductase, and/or an alcohol dehydrogenase. The system comprises an alcohol production vessel and a production substrate feed source. The production system is configured to feed the source of impure alcohol from the alcohol production vessel to the fatty ester production vessel. The fatty ester production vessel and the alcohol production vessel are a same vessel. The production system further comprising a production substrate storage unit in fluid communication with the fatty ester production vessel. The production substrate storage unit is in fluid communication with the alcohol production vessel. The source of impure alcohol comprises an alcohol composition containing (1-25% alcohol by volume). The alcohol production vessel is separate from and in fluid communication with the fatty ester production vessel, and the vessel is configured to produce and feed an alcohol product to the fatty ester production vessel. Preferred Components: The alcohol composition comprises at least one alcohol of the formula R1-OH. The alcohol comprises an aliphatic group having at least 1 carbon atom or an alkyl group having at least 2 carbon atoms (preferably ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isoamyl alcohol, isopentenol, hexanol, heptanol, octanol, nonanol, decanol, geraniol, undecanol, uodecanol, tetradecanol, pentadecanol and/or farnesol; especially ethanol). The alcohol composition further comprises an alcohol production host and an alcohol production substrate. The fatty ester production substrate is provided in the alcohol composition. The alcohol production substrate and the fatty ester production substrate are selected from monosaccharide, glucose, fructose, mannose, galactose, oligosaccharide, fructo-oligosaccharide, galacto-oligosaccharide, polysaccharide, xylose, arabinose, disaccharide, sucrose, maltose, turanose, cellulosic material, methyl cellulose, sodium carboxymethyl cellulose, succinate, lactate, acetate, starch derivatives and/or lignocellulosic biomass (preferably glucose). The fatty ester is an ethyl ester.R1=optionally saturated, branched carbon chain, an alkyl carbon chain, a straight chain alcohol or 1-20C (preferably 3-16C) aliphatic group.Preferred Composition: The fatty ester composition further comprises a detectable amount of at least one impurity selected from mannitol, cellulose, hemicelluloses, starch, soluble polysaccharides, dextran, phytoglycogen, potassium, sodium, calcium, magnesium, chlorides, bicarbonate, sulfate, phosphate, iron, aluminum, silica, ammonium, nitrate, ketones, polyols, dihydroxyacetone, furfural, hydroxymethylfurfural, Amadori products, Heyns products, pyrrole derivatives, pyridine derivatives, imidazole derivatives, pyrazine derivatives, heterocylcic caramel products, alicyclic caramel products, H-bonded caramel products, phenolic based colors, cis-aconitic acid, trans-aconitic acid, tartaric acid, citric acid, fumaric acid, malic acid, succinic acid, shikimic acid, 2,4-dihydroxybutyric acid, methylglyceric acid, saccharide acids, palmitic acid, oleic acid, linoleic acid, linolenic acid, acetic acid, lactic acid, formic acid, glyceric acid, oxalic acid, glycolic acid, aromatic acids, ferulic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, 3,4- dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, phenolics, lignin, chlorogenic acid, neutral phenolics, glycosidic flavinoids, luteolins, 6-methoxyluteolin, apigenins, tricins, fats, phosphatides, chlorophyll A, chlorophyll B, carotene, xanthophyll, anthocyanins, phosphatidylethanolamine, lecithin, vitamins, thiamine, riboflavin, pyridoxine (B6 group), niacin, calcium pantothenate, biotin, folic acid, betaine, amides, acetamide, lactamide, N-sugar color, pyrollidone carboxylic acid (PCA), allantoin, allantoic acid, aspartic acid, asparagine, asparagine, glutamic acid, glutamine, glutamine, alpha -alanine, valine, gamma -aminobutyric acid, threonine, isoleucine, glycine, leucine, lysine, serine, arginine, phenylalanine, tyrosine, histidine, hydroxyproline, proline, methionine, tryptophan, uridine, adenine, pesticides, herbicides, aldrin, dieldrin, chlordane, trehalose, acetaldehyde, acetals, 3-methyl-1-butanol, 2-methyl-1-propanol, 2-propanol, 1-propanol, 1-butanol, 2-methylbutanol, sulfite waste liquor, fusel alcohols, n-pentanol, n-hexanol, n-heptanol, higher straight-chain aldehydes, pentanal, hexanal, heptanal, octanal, aromatic alcohols, phenol derivatives, silica, maillard, caramel color, organic acids, aromatic acids, polypeptides, nucleic acids, fructose, iso-maltose, sorbitol, erythritol, glycerol, and/or lactobacillus. The composition further comprising an additional impurity containing a starch derived from a plant selected from barley, corn, wheat, potato, or rice. The fatty ester has a fraction of modem carbon of 1.003 to 1.5. The fatty ester composition comprises a mixture of fatty esters selected from C12:0, C12:1, C14:0, C14:1, C16:0, C16:1, C18:0 or C18:1, where at least 60% by volume of the fatty esters are C16 and/or C18. The fatty ester has the formula B1COOA. The B1 side of the fatty ester is a carbon chain comprising at least 6 carbons and the A side is an aliphatic group that comprises at least one carbon. The B1 side of the fatty ester is a polyunsaturated carbon chain, a monounsaturated carbon chain or a saturated carbon chain. The aliphatic group of the A side of the fatty ester has 1-20 carbon atoms. The B1 side of the fatty ester comprises a carbon chain having 5-30 (preferably 14, 15 or 16) carbon atoms. The fatty ester has a delta 13 of -10.9 to -15.4, greater than or equal to -28 (preferably -18), -27 to -24 or -16 to -10. The fatty ester has a fM 14C of at least about 1 (preferably 1.01, especially 1-1.5, particularly 1.04-1.18, more particularly 1.111-1.124). EXAMPLE - The Escherichia coli C41 production host was transformed with plasmid pCOLADuet-1-atfA (plasmid carrying an ester synthase gene), plasmid pMAL-c2X-TEchfatB3 (a thioesterase gene), and plasmid pCDFDuet-1-fadD (a fadD gene from Escherichia coli). This recombinant strain was grown at 25 degrees C in M9 medium (medium containing 0.5% D-glucose and 0.1% of 4-phenoxy-n-butyric acid ethylester) (3 ml) with kanamycin (50 mg/l), carbenicillin (100 mg/l), and spectinomycin (100 mg/l). After isopropyl beta D-thiogalacto pyranoside (IPTG) induction, the media was adjusted to a final concentration of 1% ethanol and 2% glucose. The culture was allowed to grow for 40 hours after IPTG induction. The cells were separated from the spent medium by centrifugation at 3500 x g for 10 minutes. The cell pellet was re-suspended with M9 medium (3 ml). The cell suspension and the spent medium were then extracted with 1 volume of ethyl acetate. The resulting ethyl acetate phases from the cells suspension and the supernatant were subjected to GC-MS analysis. The 16C ethyl ester was the most prominent ester species and 20% of the fatty ester produced was released from the cell. A control Escherichia coli strain C41 containing pCOLADuet-1 (empty vector for the ester synthase gene), pMAL-c2X-TEchfatB3 (containing fatB3), and pCDFDuet-1-fadD failed to produce detectable amounts of fatty esters.