Intrinsic Activity of Inulinase from Kluyveromyces marxianus ATCC 16045 and Carbon and Nitrogen Balances

Kluyveromyces marxianus ATCC 16045 was cultivated in a batch on minimal medium to overproduce inulinase. The fermented broth was purified by fast protein liquid chromatography and ultrafiltration, and a pure enzyme fraction was obtained. SDS-PAGE electrophoresis allowed calculating molecular mass of 59 kDa, while nitrogen determination by the micro-Kjeldahl method allowed evaluating intrinsic inulinase activity of 879 IU/mg. These results were then used to perform material balances of the fermentation process, which suggested that no more than 0.1 % either of carbon or nitrogen initially present in the medium were incorporated in the extracellular inulinase released under different cultivation conditions. The information obtained in this study can be used for future proposal of metabolic models describing inulinase overproduction by this yeast.