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Saccharomyces diastaticus cells were immobilized onto beech wood chips of different particle size and three pH values. pH values in the range 5.0-6.0, and 1.84-1.92 mm particle size had a positive effect on the immobilization process. The chosen carrier--1.84 mm-sized wood chips adsorbed 150 mg dry cell mass per g dry carrier mass. The Gibbs free energy and the activation energy for the first (monolayer) and second (multilayer) immobilization stages was 4581, 19,090 and 8590 J g mol-1, respectively. The kinetics of immobilized cell systems in ethanol production have been studied in a packed bed-reactor. Ethanol production and the respiration quotient (RQ) were at a maximum at a dilution rate of 0.16/h. The reactor was operated under steady-state conditions for 30 d at the dilution rate 0.16/h.

Jerusalem artichoke (JA) is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as ethanol, is an important objective in industrial biotechnology. In this study, ethanol was efficiently produced from the hydrolyzates of JA obtained at different pH values (pH 2.5, pH 3.0 and pH 3.5), temperature (120, 130, 132 and 134?C) and hold time (30 and 60 min) by Saccharomyces cerevisiae. The efficient degradation of JA by HCl under certain experimental conditions was confirmed by thin-layer chromatography. Ethanol concentration of 7.52% (w/w), which corresponds to 93.89 % of the theoretical yield is achieved by ethanol fermentation of JA hydrolyzate obtained at pH 2.5. [Projekat Ministarstva nauke Republike Srbije, br. TR-31002]