ISSN 0103-9016. <a href="http://dx.doi.org/10.1590/S0103-90162005000300014.Biodiesel">http://dx.doi.org/10.1590/S0103-90162005000300014.Biodiesel</a> consists of long-chain fatty acid esters, derived from renewable sources such as vegetable oils, and its utilization is associated to the substitution of the diesel oil in engines.