(316a) Effects of Carbon Sources, Oxygenation and Ethanol On the Production of Inulinase by K. marxianusYX01

Inulinase is one of the most important factors of the consolidated bioprocessing (CBP), which combines enzyme production, inulin saccharification, and ethanol fermentation into a single process. In this article, the inulinase production and cell growth on the K. marxinaus YX01 under different conditions were studied.  Carbon source was shown to be less significant on the production of inulinase although the activity of inulinase was a little higher using inulin as carbon source than using glucose or fructose. The concentration of the carbon sources had a great repression effect on the activity of inulinase, when the concentration is up to 60g/L, the activity of the inulinase was only 50% of that of 20g/L. The enzyme activity was strongly influenced by aeration rate. It has been shown that the activity of inulinase and cell growth under anaerobic conditions both kept at a low level but aeration at 1.0 vvm (air volume/broth volume·minute) led to higher activity. It is interestingly that the inulinase activity per unit biomass did not show significant differences under different aeration rates. Ethanol had great repression on the cell growth. The cell stopped to grow when the addition ethanol was over 9% (v/v), but ethanol did not restrain the activity of secreted inulinase and the enzyme was stable under 15% ethanol addition.