Degnechew Demisu - Ethiopian Forestry Development, Forest Products Innovation Center, Addis Ababa, Ethiopia.
S. Kebede - Addis Ababa University, Addis Ababa Institute of Technology, School of Chemical and Bioengineering, King George VI St., Addis Ababa, Ethiopia.
Daniel Wondifraw - Ethiopian Forestry Development, Forest Products Innovation Research Directorate, Addis Ababa, Ethiopia

Biodiesel has been considered as biodegradable, green, cleaner, alternative, renewable and eco-friendly energy source. It can supersede petrol-diesel and help to solve challenges accompanied with energy crisis, socio-economic, environmental pollution, climate change and global warming. Hybridization of vegetable oils to synthesize biodiesel while improving fuel quality has not been studied extensively. Thus, the aim of this study was hybridization of M. stenopetala and A. indica seed oil to synthesize biodiesel and thereby improving the fuel quality. Response Surface Methodology, Box-Behnken Design, was employed in experimental design and result analysis. Oil mixing composition, reaction time and catalyst dose were selected as factors of study with three levels: low (-۱), medium (۰) and high (+۱). Other parameters, temperature, alcohol to oil molar ratio and mixing speed were kept constant. The oil hybrid compositions were: M۷۵N۲۵ (۷۵%v/v M. stenopetala oil and ۲۵%v/v A. indica oil), M۵۰N۵۰ (۵۰%v/v M. stenopetala oil and ۵۰%v/v A. indica oil) and M۲۵N۷۵ (۲۵%v/v M. stenopetala oil and ۷۵%v/v A. indica seed oil) with their corresponding biodiesel, BM۷۵N۲۵, BM۵۰N۵۰, BM۲۵N۷۵ respectively. The catalyst dose of: ۱, ۱.۵ and ۲ %w/v potassium hydroxide flake; and reaction time of ۲۰ min, ۴۰ min and ۶۰ min were considered as variables of study. Fifteen experimental runs were conducted with three levels for each factor. Quadratic model was developed with statistical significance, P - value < ۰.۰۰۰۱. Analysis of variance (ANOVA) and determination of coefficients were used to evaluate the model quality, where the main comparison was conducted at ۵% Least Significant Difference.

Azadirachta indica, Biodiesel, hybridization, Moringa stenopetala, Transesterification