BACKGROUND Luffa cylindrica has numerous domestic and industrial uses. For example, this natural fiber supports immobilization through the covalent bonding of an inulinase. In addition, fructose syrup from crude inulin obtained from prickly pear (Opuntia ficus-indica) can be obtained in a plug-flow mini reactor with this immobilized inulinase on L. cylindrica. RESULTS A central composite design of experiments was used to maximize the enzymatic fructose production from crude inulin obtained from Opuntia ficus-indica in a plug-flow mini reactor. The experiments explore temperature (between 45 and 55 C), pH (4.0–5.0), and feed flow (0.1–0.2 ml/min). After verifying the adequacy of the quadratic model for productivity, it was maximized to find the optimal condition. It was at 49.97 C, 4.6 and 0.20 ml/min for the temperature, pH, and flow, respectively. Under the optimal condition, the quadratic model suggested a productivity of 2.456 ± 0.015 mg/h. Three validation experiments confirmed the validity of the model. CONCLUSIONS The results confirmed the suitability of L. cylindrica as support for the immobilization of inulinase