Biogas is gaseous material produced during anaerobic
digestion of organic compound. Biogas holds wide applications
such as fuel for electricity, car, cooking, lightening,
and heating. Among these applications, conversion of orange
peels wastes into fuel is attractive, since it gives benefits in
terms of both energy recovery and environmental aspects.
Orange peel waste contains both soluble and insoluble carbohydrates
that can be digested to biogas [11]. However, the
main challenge to produce biogas from orange peel is the
presence of an antimicrobial compound “D-limonene.” This
chemical constitutes 90% of oranges essential oil as 2-3% of
dry matter of the orange [11]. Limonene has been reported
to be highly toxic to anaerobic digestion [11–13]. It causesultimate failure of the process at concentration of 400