Effects of Oil Extraction on Ethanol and Biogas Production from Eruca sativa Seed Cake

Abstract

Ethanol and biogas are promising alternative fuels that can be produced from inedible agricultural wastes. However, a pretreatment step is needed to make these substrates amenable to the microbial digestion. The residue of vegetable oil extraction process, called seed cake, offers potential as a feedstock for ethanol and biogas production. However, the oil extraction process may affect the performance of further processes. In this study, the effect of mechanical and solvent extraction methods of Eruca sativa grains was studied on the further ethanol and biogas production from its seed cake. The mechanically extracted seed cake (MESC) and solvent extracted seed cake (SESC) were subjected to NaOH pretreatment prior to ethanolic fermentation and anaerobic digestion. The pretreatment offered positive effects on glucose and ethanol production yield from both type of seed cake; however, the results were more promising on MESC, in which the yield improved by 301.7 %. In case of biogas production, the pretreatment substantially increased the methane production from the MESC by 105.6 %, while it showed negative effects on the SESC. The current study suggested that the oil extraction method can affect the performance of further processes on seed cake for biofuel production, especially biogas.