In the present study, a highly efficient CaO-based catalyst was synthesized by using abalone shell as a precursor and ethanol as a modification agent for biodiesel production. The physico/chemical properties of the catalysts, which could be tailored by altering the ethanol-treatment temperature (room temperature, 100 degrees C and 160 degrees C), were monitored by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis and Hammett indicator. Once treated with ethanol, the modified CaO (M-CaO) catalyst exhibited an increased catalytic activity mainly due to the high surface area, increased specific basicity and decreased crystalline size compared to the unmodified CaO (U-CaO) catalyst Particularly, when the ethanol treatment temperature was 100 degrees C, the maximal yield of fatty add methyl ester (FAME) for the M-CaO catalyst could reach 96.2% (87.5% for the U-CaO catalyst). Furthermore, the M-CaO catalyst exhibited good reusability, having a superior catalytic activity compared to the U-CaO catalyst after recycling for more than five cycles. (C) 2015 Elsevier B.V. All rights reserved.