Recently interest has been revived in the use of plant-derived waste oils as renewable
replacements for fossil diesel fuel. Oliveepomace oil (OPO) extracted from alperujo (byproduct
of processed olives for olive oil extraction), and produced it in considerable
quantities throughout the Mediterranean countries, can be used for biodiesel production. A
steam treatment of alperujo is being implemented in OPO extraction industry. This steam
treatment improves the solideliquid separation by centrifugation and facilitates the drying
for further extraction of OPO. It has been verified that the steam treatment of this byproduct
also increases the concentration of OPO in the resulting treated solid, a key factor
from an economic point of view. In the present work, crude OPO from steam-treated
alperujo was found to be good source for producing biodiesel. Oil enrichment, acidity,
biodiesel yield and fatty acid methyl ester composition were evaluated and compared with
the results of the untreated samples. Yields and some general physicochemical properties
of the quality of biodiesel were also compared to those obtained with other oils commonly
used in biodiesel production. As for biodiesel yield no differences were observed. A
transesterification process which included two steps was used (acid esterification followed
by alkali transesterification). The maximum biodiesel yield was obtained using molar ratio
methanol/triglycerides 6:1 in presence of sodium hydroxide at a concentration of 1% (w/w),
reaction temperature 60 C and reaction time 80 min. Under these conditions the process
gave yields of about 95%, of the same order as other feedstock using similar production
conditions.