Performance of a continuous bioreactor with immobilized yeast cells in the ethanol fermentation of molasses-stillage medium

Sánchez, Esteban; Alhadeff, Eliana M.; Rocha-Leão, Maria Helena M.; Fernandes, R C; Pereira, Nei

doi:10.1007/bf00137817

Cited by 19 publications

(10 citation statements)

References 7 publications

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“…In general, 6-12% increase in ethanol production has been reported in immobilized yeast/Z. mobilis cells (entrapped in calcium alginate matrix) over free cell from various substrates such as glucose (Bravo & Gonzalez 1991), molasses (Sanchez 1996), cassava starch hydrolysate (Vijayagopal & Balagopalan 1989) and sweet potato (Yu et al 1996). The advantage of using immobilized cells was that the cells survived and were active on the support used for immobilization for four cycles of fermentation, which could save considerable time and energy.…”

Section: Resultsmentioning

confidence: 99%

Ethanol fermentation of mahula (Madhuca latifolia) flowers using free and immobilized bacteria Zymomonas mobilis MTCC 92

2010

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Mahula (Madhuca latifolia L.) is a deciduous tree commonly found in the tropical rain forests of Asian and Australian continent. Corolla, the edible part of its flowers, is rich in fermentable sugar (37 ± 0.23%; on dry weight basis). Batch fermentation of mahula flowers was carried out using Zymomonas mobilis MTCC 92 free cells and cells immobilized in calcium alginate matrix. The ethanol productions were 122.9 ± 0.972 and 134.6 ± 0.104 g/kg flowers on dry weight basis using free and immobilized cells, respectively, after 96 h of fermentation, which showed that cells entrapped in calcium alginate matrix yielded 8.7% more ethanol than free cells. Further, the immobilized cells were physiologically active up to three more cycles of fermentation producing 132.7 ± 0.095, 130.5 ± 0.09 and 128.7 ± 0.056 g ethanol per kg flower in first, second and third cycle, respectively.

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Section: Resultsmentioning

confidence: 99%

Ethanol fermentation of mahula (Madhuca latifolia) flowers using free and immobilized bacteria Zymomonas mobilis MTCC 92

2010

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“…Brazil is pioneer in large scale motor fuel ethanol production through the fermentation of sugar cane molasses by yeast (Sanches et al, 1996;Wheals et al, 1999). However, 30% of the industries have substituted batch by continuous fermentation processes (Wheals et al, 1999) because this presented several advantages.…”

Section: Introductionmentioning

confidence: 99%

“…However, 30% of the industries have substituted batch by continuous fermentation processes (Wheals et al, 1999) because this presented several advantages. To improve the productivity and ethanol yield and to avoid the utilization of centrifuges that are expensive, continuous processes with immobilized cells in different carriers as glass, synthetic polymers as polyacrylamide (Lida, 1993) and polypropilene gels (Inloes et al, 1983), calcium alginate (Bravo and Gonzales, 1991;Gilson and Thomas, 1995;Roukas, 1994;Sanches et al, 1996), kissiris (Argiriou et al, 1996) have been suggested, although some carriers presented difficulties at industrial scale. For example, alginate beads that can be destroyed due to friction and CO 2 evolution inside the beads (Gilson and Thomas, 1995).…”

Section: Introductionmentioning

confidence: 99%

Ethanol fermentation of a diluted molasses medium by Saccharomyces cerevisiae immobilized on chrysotile

Alegre

Rigo

Joekes

2003

Braz. arch. biol. technol.

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In this work, the catalytic role of chrysotile support on the acceleration of alcoholic fermentation under non-aseptic conditions by Saccharomyces cerevisiae was investigated. The fermentation medium employed consisted only of diluted sugar-cane molasses. In the batch fermentations process with immobilized yeasts, the initial rate of CO 2 production increased roughly 27 % during the first 30 minutes, compared to systems containing no chrysotile. A study of continuous alcoholic fermentation with chrysotile in the reactor bed showed a higher ethanol production rate at the different dilution rates investigated compared to similar fermentations without chrysotile.

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“…On the basis of these results it would appear that a dilution yielding a sugar concentration of 100 g/l was optimal in the continuous-¯ow bioreactor system under the reported operating conditions. Although the volumetric productivities from this system were relatively low, particularly in comparison with previous studies using either alginate-immobilized K. marxianus IMB3 [11], kissiris-immobilized K. marxianus IMB3 [16] or indeed alginate-immobilized Saccharomyces cerevisiae [13] it should be noted that the column bioreactor dimensions were much lower in this case and the beads contained a lower cell density than those used in the quoted work above relating to the use of S. cerevisiae.…”

Section: Cells/bead Inmentioning

confidence: 76%

“…Beads were dissolved in phosphate as described previously [13] and the viable cell count was determined by plating dilutions onto agar plates containing yeast growth medium [1].…”

Section: Yeast Cell Viabilitymentioning

confidence: 99%

Continuous ethanol production from molasses at 45 °C using alginate-immobilized Kluyveromyces marxianus IMB3 in a continuous-flow bioreactor

Gough¹,

McHale²

1998

Bioprocess Engineering

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The thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus IMB3 was immobilized in calcium alginate and used in a continuous¯ow bioreactor to produce ethanol from molasses at 45°C. The molasses was diluted to yield a number of ®nal sugar concentrations and the effect of molasses sugar concentration on ethanol production by the continuous system was examined. Although maximum ethanol concentrations were obtained using sugar concentrations of 140 g/l, within 10 h of introducing the feed to the column bioreactors, those ethanol concentrations subsequently decreased to lower levels over a 48 h period. Examination of viable yeast cell number within the immobilization matrix indicated a dramatic reduction over this time period. At lower molasses concentrations, ethanol production by the continuous¯ow system remained relatively constant over this time period. In addition, the effect of residence time on ethanol production by the continuous¯ow bioreactor was examined at a ®xed molasses sugar concentration (120 g/l) and a residence time of 0.66 h was found to be optimal on the basis of volumetric productivity. Ef®ciencies of the continuous¯ow bioreactor con®guration used in these studies ranged from 31±76%. IntroductionSince the ®rst report of its isolation in 1992 the thermotolerant yeast strain Kluyveromyces marxianus IMB3 has emerged as a realistic candidate for commercial ethanol production at elevated temperatures [1]. Advantages associated with producing ethanol at elevated temperatures include rapid bioconversion rates, decreased risk of contamination and in certain cases, increased ef®ciency with respect to product recovery. Another advantage associated with the use of this particular yeast strain include its ability to convert a wide range of simple carbohydrates such as glucose, galactose, sucrose, lactose and cellobiose to ethanol [2±5]. It has been found that the microorganism is capable of utilizing disaccharides such as sucrose, lactose and cellobiose as a result of its ability to produce invertase, b-galactosidase and b-glucosidase, respectively. In addition, the versatility of this microorganism with respect to growth characteristics and ethanol production is demonstrated by its ability to co-exist in fermentation together with the thermophilic amylolytic and cellulolytic ®lamentous fungus Talaromyces emersonii CBS 814.70 and this mixed culture system has been exploited in the conversion of starch to ethanol [6]. It has also been found that this yeast strain is suitable for use in simultaneous sacchari®cation and fermentation systems concerned with bioconversion of cellulose to ethanol as a result of increased thermal compatibility between cellulolytic enzymes and the growth temperature of the microorganism [7].More recently it has been shown that it is possible to immobilize this yeast strain in alginate-based matrices and the functionality of this biocatalyst preparation with respect to ethanol production has been examined using a variety of bioreactor con®gurations and substrates. In add...

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Performance of a continuous bioreactor with immobilized yeast cells in the ethanol fermentation of molasses-stillage medium

Cited by 19 publications

References 7 publications

Ethanol fermentation of mahula (Madhuca latifolia) flowers using free and immobilized bacteria Zymomonas mobilis MTCC 92

Ethanol fermentation of mahula (Madhuca latifolia) flowers using free and immobilized bacteria Zymomonas mobilis MTCC 92

Ethanol fermentation of a diluted molasses medium by Saccharomyces cerevisiae immobilized on chrysotile

Continuous ethanol production from molasses at 45 °C using alginate-immobilized Kluyveromyces marxianus IMB3 in a continuous-flow bioreactor

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