Bioproduction of Fructose from Chicory (Cichorium intybus) Roots and Jerusalem Artichoke (Helianthus tuberosus)Tubers

Fructose is a natural sugar widely used in beverage production and pharmaceutical industries . Therefore, the present study aimed to utilize the chicory roots (Cichorium intybus) and Jerusalem artichoke tubers (Helianthus tuberosus) extracts as inulin source for the production of fructose by inulinase (EC 3.2.1.80) hydrolysis . Aspergillus strain was isolated from sugarcane bagasse and identified as A.niger isolate MonEg (GQ890276) using PCR system. Under the optimized conditions, the aforementioned A. niger isolate produced maximum inulinase (54.70 U/ml) on a medium containing chicory roots powder as a carbon source after 72hr at 30°C. The specific activity of the enzyme was 21.06 U/mg toward inulin with a purification fold of 6.77 with ammonium sulphate precipitation at pH 5.5 and 50°C. The enzyme incubated with extracts of chicory roots (CR ) and Jerusalem artichoke (JA) was prepared in 0.1M sodium acetate buffer (pH 5.5) at 50°C. The products of the enzymatic reaction were analyzed by dinitrosalicylic acid and HPLC. Data showed that the fructose yield ranged from 0.31 to 0.60 g/ g of inulin in the samples after 3 hr of reaction and nearly 58% and 39% of initial inulin had been hydrolysed under the same conditions in CR and JA samples, respectively. The fructose productivities were 0.57g /100ml/ hr and 0.31g /100ml/ hr for CR and JA samples, respectively. At a constant initial inulin concentration and changes in enzyme activity level, the fructose productivity increased to 0.48g /100ml/ hr in JA samples after 3 hr of incubation .So, chicory roots and Jerusalem artichoke are considered as natural inulin source that can be utilized for the production of fructose. The chicory powder is considered as a good source of carbon for inulinase production