NOVELTY - Method (M1) for producing a fatty acid methyl ester involves: providing a fatty ester production host; providing methanol to the fatty ester production host; and converting the methanol to fatty acid methyl ester by using the fatty ester production host.    USE - For producing a fatty acid methyl ester; useful for forming a biofuel (preferably biodiesel) (claimed). The fatty esters are also useful as a surfactant; or as the intermediate for the synthesis of a commodity, specialty, or fine chemicals such as fuels, alcohols, olefins, and pharmaceuticals. Also useful for producing fatty acid derivatives such as acyl-acyl carrier protein (ACP), acyl-coenzyme A (CoA) and other fatty acid derivatives such as short and long chain alcohols, fatty acids, hydrocarbons, fatty alcohols, esters including waxes or fatty esters, diesel and gasoline.    ADVANTAGE - The method provides fatty acid ester (such as methyl ester) production method and compositions, by using biological production host, so that the fatty acid ester can be utilized as biofuel (e.g. biodiesel) i.e. as renewable fuel; as compared to the prior art method in which the biological production host is utilized to produce specific fatty ester, which can then be incorporated or modified into biofuel, to obtain desired fuel properties such as cloud point, cetane number (CN), viscosity, and lubricity that changes considerably depending on alcohol moiety incorporated into fatty ester; in which when properties of a single specific fatty ester are ideal for its use, relatively little additional manipulation is required to use fatty ester as or in fuel; but in situations where the inherent properties of specific fatty ester are not ideal, subsequent manipulation of composition is required so that a final product with the desired properties is achieved. The method provides an improved method for production of fatty acid methyl ester, in which the properties of fatty ester composition can be manipulated through the use of a combination of different fatty esters (e.g. fatty esters having different degrees of unsaturation or chain lengths) so that resulting fatty ester mixture has desired properties. This is achieved by producing the various fatty ester compositions, via the production hosts, and then combining fatty ester products to achieve desired fatty ester composition. While post production combination is one way for obtaining a desired fatty ester mixture, the production of fatty esters in production hosts provides opportunity to tailor final fatty ester mixture through various, earlier, biological manipulations. The customization process for producing a desired fatty ester mixture can begin before any fatty ester is present. By selecting various types and/or amounts of alcohols to combine with a fatty ester production host, it is possible to make a variety of fatty esters concurrently. This in turn allows obtaining desired final combination of fatty esters, with desirable properties as a mixture (such as desired cloud point, cetane number, viscosity and lubricity), and eliminates or reduces need for subsequent manipulation of fatty ester product in its adaptation to fuel. Further, the method has numerous advantages such as the method allows for reduction in number of production, concentration, or purification steps; also removes or reduces need for combining various fatty esters to obtain product with desired properties; allows for reduction in space and/or increase in speed in which final fatty ester mixture can be created; and allows for single vessel to serve for fatty ester production process so that mixing and storing vessels can be reduced or eliminated. The fatty ester production host produces fatty acid methyl esters at a titer of ( greater than or equal to 100, preferably greater than or equal to 250, especially greater than or equal to 500) mg/L; and has a specific productivity for fatty esters of ( greater than or equal to 30, preferably greater than or equal to 40, especially greater than or equal to 50) mg/L/optical density (OD)600. In the fatty ester composition (C1) the fatty acid methyl ester has a fraction of modern carbon of (1.003-1.5, preferably 1.111-1.124); and a delta 13C of (-10.9 to -15.4, preferably -13.84 to -13.92). An additional advantage of production host system is ability to produce primarily or only saturated and monounsaturated fatty esters; in contrast, plant oils are rich in di- and tri- unsaturated fatty acids, which are less stable to oxygen, and result in significant handling and storage constraints. Using the method, fuels comprising relatively heterogenous fatty acid derivatives that have desired fuel qualities can be produced. Such fuels can be characterized by carbon fingerprinting or their lack of impurities when compared to petroleum derived fuels or biodiesel derived from triglycerides. The fuels comprising the fatty acid derivatives contain less of some types of impurities that are normally associated with biofuels derived from triglycerides i.e. fuels derived from vegetable oils and fats. The crude fatty acid derivative biofuels produced by the method (prior to mixing fatty acid derivative with other fuels, such as traditional fuels) contain less transesterification catalyst (e.g. hydroxide catalysts such as NaOH, KOH, LiOH; or acidic catalysts such as mineral acid catalysts and Lewis acid catalysts) than petrochemical diesel or biodiesel e.g. contain less than 2-0 vol.% of transesterification catalyst or impurity resulting from transesterification catalyst.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) fatty ester composition (C1) comprising: production host, and fatty acid methyl ester of formula B''COOCH3; and    (2) a biofuel comprising: the fatty ester composition (C1).    B''= greater than or equal to 6C chain that.