Inulinase Production by Filamentous Fungi Indigenous to Saudi Arabian Soils

Abstract

represents a source for the production of oligosaccharides by enzymatic hydrolysis (inulinase enzyme) that is used widely in industrial and medical applications. This research aims to identify the filamentous fungi indigenous and occupant and grow the filamentous fungi, then assess the thermotolerant inulin-degrading fungal isolates and investigate the higher yield produced by local fungal stains of inulinase enzyme, and comparing with reference ones, as well as Identify the growth parameters conditions that affecting on enzyme production local fungal strains. Fourteen agricultural soil samples were collected from the top layer (0-15 cm) from different regions of the territory of the Kingdom of Saudi Arabia (by placing 100 g of the soil sample from each region), depending on the climatic differences. Soil sample sites were Mecca, Al- Riyadh, AlQassim, AlBaha, AlGouf. The fungi produced inulinase enzymes are isolated and incubated at 28-30°C for 10 days, then DNA was isolated and tested for thermo-tolerance. In addition to this, the inulinase enzyme in liquid media (time course) was assessed and the optimum production conditions were studied (Agitation, temperature, pH, the concentration of inulin, carbon sources, nitrogen source). There are thirty fungal isolates from twelve soil samples, they belong to Aspergillus, Fusarium, Penicillium, Trichoderma, Rhizoctonia, Mucor, Alternaria, and Rhizopus genus. The inulinase enzyme activity ranged between 11.76-39.16 U/ml, as well as the optimum production conditions, are: agitation at 150 rpm, incubation temperature at 30°C, pH 6, 2% of inulin concentration, maltose as carbon source, and tryptone as a nitrogen source. Finally, high inulinase productivity was obtained by local fungal strain in this study.