The interaction effects of variables on inulinase production were studied by plotting 3D surface plot against any two independent variables, as in Figs. 2–4. The results illustrated graphically in these figures indicated that the dependency of inulinase enzyme on initial pH level and the incubation temperature followed by the concentration of KH2 PO4 as an energy source. The inulinase activity increased with increasing the initial pH level to 7.5 and 8.5, where the neutral to alkaline range was observed to be most favourable conditions for inulinase production by this strain than the acidic conditions. This to some extend agreed with who found that the maximal inulinase activity of Xanthomonas campestris pv. phaseoli KM24 mutan was obtained when the ini-tial pH of the culture medium was adjusted to 7.0. Previous studies indicated that Geofungi growing in marine environments appear to be conditioned to their environment The optimum temperature favouring inulinase production is 30 ◦ C, also the activity increased at 35 ◦ C but decreased greatly at the temperature 40 ◦ C.