Yeasts immobilized

Because the presence of yeasts can represent a logistical bottleneck in postfermentation clarification, an alternative that has been studied is the use of immobilized microorganisms. Here, yeasts are trapped in calcium alginate beads or strands that are collectively packed into a synthetic mesh sleeve that is immersed into the juice/must. Relatively few yeasts ( 10V mL) escape the encapsulation matrix (Yokotsuka et al., 1993) but yet conduct an active alcoholic fermentation. Yajima and Yokotsuka (2001) reported that concentrations of some undesirable volatile compounds (methanol, ethyl acetate, and acetaldehyde) were lower in wines made using Saccharomyces immobilized in double-layer beads. Immobilized yeasts 

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Bravo, P., and Gonzalez, G., Continuous Ethanol Fermentation by Immobilized Yeast Cells in a Fluidized-Bed Reactor, J. Chem. Tech. Biotechnol., 52 127 (1991)... 

Vorlop, K. D., Estape, D., and Gddia, F., Design of Ca-Alginate Immobilized Yeast Cell Beads with Controlled Low Density to Enhance Their Fluidization Behaviour in Bioreactors, Biotechnol. Tech., 7 287 (1993)... 

Kakuta T, Tateno Y, Koizumi T et al (1992) Azo dye waste-water treatment with immobilized yeast. J Soc Ferment Technol 70 387-393... 

Tata, M., Bower, R, Bromberg, S. et al.. Immobilized yeast bioreactor systems for continuous beer fermentation. Biotech. Prog., 15 (1999) 105-113. 

Hikmna M, Suzuki H, Yasuda T, Karube 1, Suzuki S (1979) Amperometric estimation of BOD by using living immobilized yeasts. Em" J Appl Microbiol Biotechn 8 289-297... 

The secondary fermentation of Champagne production is now carried out by immobilzed cell technology. Moet Chandon utilize a plug of immobilized yeast cells for bottle carbonation (Mensour et al, 1997). 

Cultor Ltd. (Finland) and Tuchenhagen(Germany) have developed a process, where yeast cells are adsorbed on the surface of the carrier developed for glucose isomerase (Spezyme, Table 6.1). The high volumetric productivity of the immobilized yeast cells make a conversion of dr-acetolactate to acetoin possible with only a few hours residence time in the packed bed columns. 

Immobilized yeast cells with an oxygen electrode (BOD monitoring) Nissin Electric Co. Ltd., Japan... 

Alcohol Sensor. On-line measurements of ethyl alcohol concentration in culture broth are required in fermentation industries. A microbial electrode consisting of immobilized yeasts or bacteria, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the determination of methyl and ethyl alcohols(7). 

Hussain F, Birch DJ, Pickup JC. Glucose sensing based on the intrinsic fluorescence of sol-gel immobilized yeast hexokinase. Analytical Biochemistry 2005, 339, 137-143. 

Qureshi, N. and Tamhane, D. V. (1986). Mead production by continuous series reactors using immobilized yeast cells. Appl. Microbiol. Biotechnol. 23, 438—439. 

Figure 5. 31P NMR magnetization transfer measurements of ATP turnover in immobilized yeast cells. A control spectrum is shown in (a). Saturation of the y-phosphate resonance of ATP and transfer of this magnetic label through chemical exchange results in a decrease in the intensity of the P, and sugar phosphate resonances (b). This is most clearly seen in the difference spectrum (a-b). The magnitude of the decrease in the P, resonance can be used to calculate the flux between P, and ATP and, hence, the rate of ATP turnover (see Brindle, 1988a,b).

Williams, D. and Munnecke, D., The production of ethanol by immobilized yeast cells, Biotechnol. Bioeng., 23, 1813-1825, 1981. 

The application of continuous processes helps to find the optimum conditions for maximum productivity and the best solvent ratios. Vacuum processes, cell recycling and immobilized yeast cells 21) have been used to increase productivity and the yield of alcohol. Cysewski et al. 22) showed an increase in the alcohol production rate from 7 to 80gl-1h-1 by the application of continuous methods with recycling at 0.066 bar oxygen pressure. 

Busova, K., Magyar, I., and Janky. F. (1994). Effect of immobilized yeasts on the quality of bottle-fermented sparkling wine. Acta Aliment. Hung., 23, 9-23. 

Fumi, M.D., Trioli, G., Colagrande, O. (1987a). Preliminary assessment on the use of immobilized yeast-cells in sodium alginate for sparkling wine processes. Biotechnol. Lett., 9, 339-342. 

Godia, E, Casas, C., Sola, C. (1991). Application of immobilized yeast-cells to sparkling wine fermentation. Biotecnol. Progr., 7, 468 70. 

Shabtai Y, Chaimonitz S, Freeman A, Katchalski KE, Linder C, Nemas M, Perry M, and Kedem O. Continuous ethanol production by immobilized yeast reactor with membrane pervaporation unit. Biotech. Bioengg. 1991 38 869-876. 

In addition, the response time of immobilized yeast to different sugars was used for monitoring and control of Bacillus licheniformis cultures (Hundeck et al. 1992). Specificity is not a characteristic of cell-based sensors rather, they are characterized by their ability to react in an integrated way to various stimuli. 

Immobilized microorganisms and enzymes are becoming commercially available. One example is co-immobilized yeast and glucoamylase (Gist Brocades NV), which is used to simultaneously saccharify starch dextrins into glucose and ferment this to ethanol in fluidized bed reactors. 

B. Godlewska-Zylkiewicz, J. Malejko, B. Lesniewska, A. Kojlo, Assessment of immobilized yeast for the separation and determination of platinum in environmental samples by flow-injection chemiluminescence and electrothermal atomic absorption spectrometry, Microchim. Acta 163 (2008) 327. 

Cellular Viability and Concentration Determined by counting cells in nine squares of a Neubauer chamber after dying them with methylene blue solution. Viable cells were not colored, and dead cells were blue free yeast concentration was also obtained by filtering a known volume of cell suspension and drying the wet mass until the constant weight was achieved viability and concentration of immobilized yeast were determined as already described, after dissolution of the pectin gel [1.0 g of cured pellets was dissolved in 20 ml of 5% ethylenediaminetetraacetic acid (EDTA) solution at constant agitation]. The cell concentration was calculated as ... 

These examples indicate the in situ applicability of enzyme electrodes however, numerous problems have still to be solved. At present, coupling of enzyme sensors for fermentation control in a bypass arrangement appears to be more favorable [412]. Following this concept, an invertase thermistor incorporating a sterilizable filter unit has been developed [413] for the monitoring of alcoholic fermentation by immobilized yeast cells. Another thermistor has been successfully used for on-line glucose measurement under real cultivation conditions of Cephalosporium acremonium [414]. Similar calorimetric devices are suitable for other fermentation processes and in environmental analysis. 

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