Sustainable biodiesel production via transesterification of waste cooking oil by using CaO catalysts prepared from chicken manure

[Display omitted] •Calcined chicken manure was successfully used as catalyst for biodiesel production.•Ca compound in chicken manure was converted into active CaO by calcination.•Chicken manure-derived catalysts show high activity towards transesterification.•Biodiesel fuels can be produced by using waste cooking oils. The low cost and efficient CaO catalysts have been successfully prepared from chicken manure by a simple calcination, in this present work. Chicken manure contains significant content of calcium compounds that can easily be converted into the active calcium oxide catalyst after calcination at 850°C under air. The Hammett indicator test showed that the obtained CaO catalyst has the basic strength in a range of 15