[Alcoholic fermentation of inulin by various strains of yeasts]

Strains of fourteen species of yeasts able to ferment inulin without previous chemical or physical hydrolysis were studied on semi-synthetic medium by evaluation of CO2 production under anaerobic conditions. Among them, Kluyveromyces cicerisporus, Candida macedoniensis and Candida utilis showed the best kinetic characteristics of fermentation. Experiments were carried out to specify the action of different parameters such as temperature, pH and exogenous ethanol concentration. The results obtained on semi-synthetic medium were confirmed on Jerusalem artichoke juice. The optimal temperature for fermentation was 35 degrees C for the three strains, but K. cicerisporus alone conserved its fermentative capacity at 40 degrees C, at low pH (3.5) and with 6% (v/v) exogenous ethanol concentration. This strain appears to be a good yeast for industrial production of ethanol from inulin substrate.