Different alpha-Fe2O3 loading (4-12 wt%) doped nanowires AlOOH/gamma-Al2O3 catalysts are synthesized using a deposition hydrothermal technique and thoroughly characterized using XRD, SAED-TEM, FTIR, UV-Vis, N-2 sorptiometry and XPS measurements. The 12 wt% alpha-Fe2O3/AlOOH(gamma-Al2O3) catalyst presented the highest fatty acid methyl ester (FAME) Yield that comprised of 100% for virgin oil and 94.3% for the waste one, all performed under mild optimized conditions (60 degrees C, methanol to oil molar ratio = 6:1, 3 wt% catalyst, reaction rate 600 rpm and within 3 h reaction time). It also shows high recyclability without significant loss in activity because of the superior large surface area (323.3 m(2)/g), high number of acid sites (0.45 mmol g(-1)), deep pore volume (0.322 ml/g) and to the exposed active site planes (110) and (214) of alpha-Fe2O3. The kinetic constant (k = 0.016-0.02 min(-1)) and the activation energy (E-a = 57.4 kJ mol(-1)) of the reaction together with Delta H double dagger (59.4 kJ mol(-1)), Delta G double dagger (+95.9 kJ mol(-1)) and Delta S double dagger (0.108 kJ mol(-1)) values elaborate that the reaction is endothermic, non-spontaneous and obey an associative path. The fuel properties derived from cottonseed oil exhibited high quality biodiesel comparable to the international (ASTM) standards. (C) 2020 Elsevier Ltd. All rights reserved.