A journal article by J.E. Andrade of the Centro de Investigacion en Materiales Avanzados (Mexico), reviews the biodiesel production process and latest trends in biodiesel research and development. Biodiesel is technically a mixture of methyl esters from the "transesterification" reaction of fatty acid components in plant/vegetable or algal oils with methanol. Glycerol is usually a by-product in the process. The transesterification reaction can be catalyzed by homogeneous catalysts (acids, bases), or heterogeneous catalysts (tungstated zirconia-alumina, sulfated zirconia-alumina, or sulphated tin oxide). The use of heterogeneous catalysts are said to provide advantages in terms of (1) ease in product separation, (2) minimizing side (soap-formation) reactions, and (3) cost effectiveness due to catalyst reuse. Enzymes (lipases) could also be used to mediate transesterification reactions. Enzymatic transesterification also provides ease of product separation, and minimal wastewater treatment needs. The latest innovations in the biodiesel production process include: (1) supercritical and subcritical alcohol transesterification, (2) microwave-assisted transesterification and (3) ultrasound-assisted transesterification. When transesterification is conducted at supercritical or subcritical conditions (at high temperature and pressure), the oil phase and the aqueous phase (containing the methanol and catalyst) become a single phase, and the reaction becomes faster. One drawback, however is the high cost of equipment and energy. Microwave-assisted and ultrasound-assisted transesterification are latest technologies which are reported to provide cost-effective and short reaction times. The full review article appears in the journal, Biomass and Bioenergy (URL above).