We report herein, Soybean oil was shaped to biodiesel using CaO as heterogeneous catalyst and acetone as cosolvent by employing transesterification reaction at room temperature. In order to prepare active CaO catalyst, waste snail shell was calcined at 800 degrees C. The prepared catalyst was characterized by XRD, SEM, TEM, EDS, TGA, FTIR, XRF, CO2-TPD, XPS and BET. Biodiesel yield of 98% was achieved with the optimized reaction parameters such as acetone loading of 20 wt% of oil, reaction time of 2 h, catalyst loading of 3 wt% and oil to methanol molar ratio of 1/6. Catalyst can be reused up to 11th cycles. It was concluded from the results that this waste material derived heterogeneous catalyst can replace homo-geneous catalyst. (c) 2020 Elsevier Ltd. All rights reserved.