Kluyveromyces fragilis (NCIM 3217), Kluyveromyces marxianus (NCIM 3231), Hansenula polymorpha (NCIM 3377). Pichia fermentan (NCIM 3408), Pichia polymorpha (NCIM 3419) and Debaryomyces castellii (NCIM 3446) were grown on an inulin-based growth medium. Only K. fragilis produced extracellular inulinase with a maximum after 36 h of growth at 25-27-degrees-C. Sucrose and fructose were weak inducers of inulinase as compared to inulin whereas with glucose the inulinase level was minimal. An aqueous extract of chicory roots containing 1%, fructan was a better carbon source than inulin and peptone was the best nitrogen source for the production of inulinase. The maximum yield of inulinase was about 7 units cm-3 of medium. The invertase to inulinase ratio of 10 in the culture filtrate was reduced to 1.6 on purifying inulinase by ethanol precipitation followed by chromatography on Sephadex G-200, DEAE-cellulose and CM-cellulose columns. Using this purification procedure. inulinase was purified 26-fold. With inulin as substrate, the shape of the velocity curve was nearer to a sigmoidal pattern whereas with sucrose the curve was hyperbolic. The molecular weight of inulinase was determined as 250 +/- 10 kDa. The crude and purified inulinase preparations did not release sucrose or oligosaccharides from inulin, indicating that the enzyme has primarily exo-inulinase activity. Using the metal-link chelation method, 40% of inulinase was immobilised on cellulose. Maximum activity of crude, purified and immobilised inulinase preparations was observed at 55-degrees-C. The half-life of immobilised inulinase at 25-degrees-C was 5 days.