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| Author(s): |
Gisele Mantei Tosetto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química |
| Defense date: | 2008-11-07 |
| Examining board members: |
Silvio Roberto Andrietta;
Daniel Ibraim Pires Atala;
Marco Antonio de Castro e Souza;
Francisco Maugeri Filho;
Cláudia Steckelberg
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| Advisor: | Silvio Roberto Andrietta |
| Abstract | |
The general objective of this project was the evaluation of the effects of some organic substances present in molasses, sugar cane on strains of yeast for industrial use. Chapter I refer to a brief introduction and history of alcoholic fermentation. In Chapter II, samples of industrial molasses were examined, from 10 units producing sugar, located in the states of Sao Paulo, Minas Gerais, Goias, and Parana, in order to determine and quantify some organic compounds present in them. In order to this, the technique for High Performance Liquid Chromatography (HPLC) was used. In Chapter III trials were conducted to choose the strains of better performance in terms of stress, using a 23 factorial planning star type with triplicate in central point. The studied factors were: the osmotic pressure (using KCl), temperature and initial concentration of alcohol. The strains Y904 and SA1 were those which stressed most. In Chapter IV were assessed the effects of organic compounds (caffeic, gallic, lactic, pyruvic, syringic, vanillic, acetic, formic, butyric and Hidroximetilfurfural acids) on the strains SA1 and Y904 by the fermentation in triplicate, using synthetic medium and control varying concentrations of each compound. Within the concentrations studied, only the gallic acid, lactic acid, acetic acid, formic, butyric and Hidroximetilfurfural demonstrated influence on the strains. The assessment of the cumulative effect of the substances when working with recycle cell is described in Chapter V. All experiments were performed in triplicate and repeated by eight consecutive times (8 cycles). The lactic acid is the substance that interfere most in income in ethanol (YP/S) and productivity, these parameters of most importance in industrial processes to produce alcohol. Moreover, the formic acid showed the smallest negative interference for almost all parameters studied. Finally in Chapter VI, were analyzed the effects of lactic acid and formic on the behavior of kinetic strains SA1 and Y904. The tests were performed in bench bioreactor for ten hours of fermentation. The lactic acid increased by inhibiting both the substrate and the product, showing to be a substance with a high degree of toxicity to the strains of yeast cells studied. YQTFU" /" alcoholic fermentation, kinetics, industrial substract, organic compounds, inhibition, yeast (AU) | |