Utilization of copra waste for the solid state fermentatative production of inulinase in batch and packed bed reactors

•PBD was employed to screen the nutrients for inulinase production using copra waste as substrate.•CCD was used to optimize the screened nutrients to enhance the production in batch reactor.•In PBR, variables like air flow rate, packing density, particle size and moisture content were optimized.•At the optimized condition the production in PBR was 18% more than the batch reactor. In this study, screening and optimization of nutrients for inulinase production using copra waste has been studied. Plackett–Burman Design (PBD) was employed to screen the significant nutrients for inulinase production. Response surface methodology (RSM) was used to evaluate the effects of nutrient components in the medium. The second order regression equation provides the inulinase activity as the function of K2HPO4, ZnSO4·7H2O and soya bean cake. The optimum conditions are: K2HPO4 – 0.0047g/gds, ZnSO4·7H2O – 0.02677g/gds and soya bean cake – 0.06288g/gds. At these optimized conditions, experiments were performed in packed bed bioreactor to optimize the process variables like air flow rate, packing density, particle size and moisture content. The optimum conditions were: air flow rate – 0.76L/min, packing density – 38g/L, particle size – 10/14 mesh and moisture content – 60%. At the optimized conditions, a maximum inulinase production of 239U/gds was achieved.