NOVELTY - Fatty acid alkyl ester is produced by providing an emulsion of naturally occurring fatty acids (e.g. animal fats), an alkaline solution (e.g. concentrated form of sodium hydroxide) and an alcohol (e.g. methanol); directly radiating the emulsion with ultrasonic energy to enhance the transesterification process; separating the transesterified emulsion into a glycerol solution and fatty acid alkyl ester using a natural gravity separatory; and washing and drying the fatty acid alkyl ester in a centrifuge to remove any remaining catalyst, alcohol, glycerol, soaps, and excess water.    USE - For producing fatty acid alkyl ester used for making biodiesel fuel for diesel combustion engines.    ADVANTAGE - The method is capable of meeting ASTM 6751-02 specifications for biodiesel without requiring additional treatment, and easily scalable from laboratory to industrial manufacturing facility with a capacity of one million gallons annual production to a facility with a production of more than 100 million gallons annual production. Through the use of ultrasonic cavitation, the size of drops in liquid phases may become effectively reduced, so that much smaller drops are produced, resulting in a much larger surface-to-volume ratio. This allows for the completed chemical reaction to be reached faster.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method for production of biodiesel fuel from an emulsion including fats, an alkaline solution and an alcohol, comprising coupling ultrasonic energy directly to emulsion from a horn maintained inside a reaction chamber at 70-80degreesC and 1-5 atm, where the ultrasonic energy is emitted to provide a density level of 18-65 Ws/ml and at frequencies of 20-50 kHz; and    (2) a biodiesel fuel comprising a fatty acid alkyl ester.    DESCRIPTION OF DRAWING(S) - The figure is a flow chart depicting the method for production of fatty acid alkyl ester.    Reactor (24)    Distribution pipes (28)    Separator (30)    Connecting pipe (34)    Final wash centrifuge (36)