Endoinulinase production by a new endoinulinase producer Aspergillus tritici BGPUP6 using a low cost substrate

Abstract

Endoinulinase is an inulolytic enzyme which is used for the production of fructooligosaccharides from inulin. A new endoinulinase producing fungal strain BGPUP6 was identified as Aspergillus tritici on the basis of its molecular characterization. Response surface methodology was used to optimize the endoinulinase production at shake-flask level from Aspergillus tritici BGPUP6 using raw Asparagus inulin as carbon source. Four independent variables (raw inulin, 2–4%; peptone, 0.3–0.7%; (NH4)H2PO4, 0.3–0.7% and pH, 4.5–6.5) were selected for the study based on the CCRD model of RSM. The other media supplements (FeSO4·7H2O, 0.001%; MgSO4·7H2O, 0.05% and KCl, 0.02%) were kept constant in the production medium, throughout the study. Endoinulinase production and biomass yield were selected as dependent responses. The optimal combination of media ingredients obtained from the study was 3% raw inulin, 0.5% peptone, 0.5% (NH4)H2PO4 and pH 5.5. Using the optimized media constituents, maximum endoinulinase production (25.01 IU/mL) and biomass yield (0.514g dry weight/50 mL) obtained were in good agreement with the predicted values. Crude enzyme produced was also used for the hydrolysis of inulin. The hydrolysate showed the presence of a mixture of fructooligosaccharides with varied degree of polymerization. This is the first report on the production of an endoinulinase from Aspergillus tritici.