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Copyright of Matica Srpska Journal for Natural Sciences is the property of Matica Srpska, Department of Natural Studies and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: This study examines the kinetics of a batch fermentation process of raw juice, an intermediate product of sugar beet processing, by free Saccharomyces cerevisiae yeast cells, with the aim of producing bioethanol. Defining the kinetics and kinetic parameters of this bioprocess may be regarded as an important step towards translating it to industrial scales (scale-up). The optimal values of the kinetic parameters were determined by fitting the models into the experimental data, i.e. by minimising the discrepancy between the model predictions and corresponding experimental data. The growth of yeast cells could be expressed by a logistic function model, which describes the growth as a function of initial biomass concentration, fermentation time, specific growth rate and final biomass concentration. The modified Gompertz model, which gives the bioethanol production lag time, the maximum bioethanol production rate and the maximum bioethanol concentration, was able to describe the formation of bioethanol as the fermentation proceeded. These models thus can be employed for further development of the bioethanol production process from sugar beet raw juice. [Copyright &y& Elsevier]

Abstract: The batch fermentation process of sugar beet processing intermediates by free yeast cells is the most widely used method in the Autonomous Province of Vojvodina for producing ethanol as fuel. In this study a process and cost model was developed for producing ethanol from raw juice. The model can be used to calculate capital investment costs, unit production costs and operating costs for a plant producing 44millionl of 99.6% pure ethanol annually. In the sensitivity analysis the influence of sugar beet and yeast price, as well as the influence of recycled biomass on process economics, ethanol production costs and project feasibility was examined. The results of this study clearly demonstrate that the raw material costs have a significant influence on the expenses for producing ethanol. Also, the optimal percentage of recycled biomass turned out to be in the range from 50% to 70%. [Copyright &y& Elsevier]

Abstract: Due to the reduction of the economic support for refined sugar efforts have been made to find new ways of using sugar beet outside food industry. This paper investigates the possibilities of introducing bioethanol co-production in Serbian sugar plants. Research shows current state of Serbian sugar industry and technical aspects of bioethanol co-production in sugar plants. These results represent important step toward mass production of bioethanol in Serbian factories. The main goals of introducing the concept of sugar and bioethanol coproduction would be efficient use of available resources for the production of energy, reduction of greenhouse gases emission, decreased dependence on import and creation of new jobs. Besides that, it would provide flexibility in terms of variation of produced quantities of sugar and ethanol, depending on the conditions prevailing on the market. [Copyright &y& Elsevier]