Applied Biochemistry and Biotechnology, Vol.98-100, 717-732, 2002
Ethanol production from olive oil extraction residue pretreated with hot water
The olive pulp fraction contained in the residue generated in olive oil extraction by a two-step centrifugation process can be upgraded by using the cellulose fraction to produce ethanol and recovering high value phenols (tyrosol and hydroxytyrosol). Olive pulp was pretreated in a laboratory scale stirred autoclave at different temperatures (150-250degreesC). Pretreatment was evaluated regarding cellulose recovery, enzymatic hydrolysis effectiveness, ethanol production by a simultaneous saccharification and fermentation process (SSF), and phenols recovery in the filtrate. The pretreatment of olive pulp using water at temperatures between 200degreesC and 250degreesC enhanced enzymatic hydrolysis. Maximum ethanol production (11.9 g/ L) was obtained after pretreating pulp at 210degreesC in a SSF fed-batch procedure. Maximum hydroxytyrosol recovery was obtained in the liquid fraction when pretreated at 230degreesC.
Keywords:olive oil extraction by-products;pretreatment;simultaneous saccharification and fermentation;ethanol;hydroxytyrosol