Screening of inulinase production strain and optimization of fermentation condition

112 strains producing inulinase were isolated from rhizosphere soil of Jerusalem artichoke in the salt -affected land. Strain A-6 was obtained and identified as Aspergillus fumigatus through observing its shape of individual bacterial colony and amplified the rRNA gene sequence using fungal universal primers ITS1 and ITS4. The effect of different factors on its enzyme production shown A-6 had a wide pH range and it could tolerate the high concentration of NaCl. After analysis of orthogonal design, the optimum condition for higher inulinase production of A-6 was determined:EJA 100g/L, YE 25g/L, NaCl 5g/L, NH4H2PO4 5g/L, pH5, 3d of growth under 30℃ and 170r/min in shake cultures. Maximal inulinase activity of A-6 was 13.29U/mL.