Biodiesel from fat or oil produces a large amount (about 10%) of glycerol
(HOCH2CH[OH]CH2OH) as a by-product. Large-scale commercial production
of biodiesel can therefore bring a huge amount of glycerol into the market. For
example, for every kg of biodiesel, 0.1 kg of glycerol is produced (86% FAME,
9% glycerol, 4% alcohol, and 1% fertilizer) (www.biodiesel.org). If produced
in the required purity (>99%), glycerol may be sold for cosmetic and pharmaceutical
production, but that market is not large enough to absorb it all. Therefore,
alternative commercial uses need to be explored. These include