NOVELTY - Producing biodiesel, comprises: preparing a catalyst mixture that includes a solid, heterogeneous catalyst and a (1-5C)alcohol; combining the catalyst mixture with a glyceride-containing feedstock to provide a reaction mixture; reacting the reaction mixture to produce glycerol and a fatty acid (1-5C)alkyl ester; recovering the catalyst from the reaction mixture; recovering an unreacted portion of the (1-5C)alcohol from the reaction mixture; separating the glycerol from the reaction mixture; and separating the fatty acid (1-5C)alkyl ester from the reaction mixture.    USE - The process is useful to produce biodiesel.    ADVANTAGE - The calcium-containing catalyst: can be a substantially insoluble catalyst, hence it is readily recovered from a reaction mixture, without wet washing or neutralization, thus facilitating separation of biodiesel products and valuable co-products (glycerol) with a high degree of purity; is readily recycled for use in subsequent catalytic reactions, thus allows the transesterification to be carried out with reduced costs and reduced environmental concerns; is readily activated, and is stable, even after repeated use in catalytic reactions; is highly active; and produces biodiesel products from a variety of feedstocks rapidly and under moderate conditions similar to those for homogeneous catalysts, where the transesterification can be carried out in a substantially continuous manner for improved efficiency and throughput, thus rendering it suitable for implementation in commercially viable plants.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a biodiesel production system (100), comprising: at least one reactor (108A) configured to react a reaction mixture to produce glycerol and a fatty acid (1-5C)alkyl ester, where the reaction mixture includes a solid, heterogeneous catalyst, a (1-5C)alcohol, and a glyceride-containing feedstock; at least one catalyst recovery unit coupled to the reactor and configured to recover the catalyst from the reaction mixture and to recycle the catalyst back to the reactor; at least one glycerol separator coupled to the reactor and configured to separate a first phase including the glycerol from a second phase including the fatty acid (1-5C)alkyl ester; a first alcohol stripper coupled to the glycerol separator and configured to recover a first unreacted portion of the (1-5C)alcohol from the first phase; a second alcohol stripper coupled to the glycerol separator and configured to recover a second unreacted portion of the (1-5C)alcohol from the second phase; and a biodiesel purification unit coupled to the second alcohol stripper and configured to separate the fatty acid (1-5C) alkyl ester from the second phase.    DESCRIPTION OF DRAWING(S) - The figure illustrates a system for producing biodiesel.    Biodiesel production system (100)    Catalyst hopper (102)    Mixer (104)    Alcohol storage vessel (106)    Reactor (108A)