Ethanol production by immobilized Saccharomyces cerevisiae, Saccharomyces uvarum, and Zymomonas mobilis

McGhee, J. E.; Julian, Grant St.; Detroy, R. W.; Bothast, Rodney J.

doi:10.1002/bit.260240512

Cited by 56 publications

(17 citation statements)

References 10 publications

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“…It was not possible to evaluate S. stipitis NRRL Y-7124 because it does not grow under strictly anaerobic conditions. S. cerevisiae NRRL Y-2034 [27] reached a maximum ethanol production of about 9.5 g/L (0.24 g ethanol/g glucose + xylose) within 12 h, with no further increase (some decrease in level was seen, possibly from evaporation) after glucose was depleted because this strain cannot utilize xylose. The mutagenized strains reached a level of ethanol production equal to the maximum level achieved by S. cerevisiae NRRL Y-2034 from 80 (strain 22-1-12) to 180 h (strain WT-1-11).…”

Section: Resultsmentioning

confidence: 99%

Random UV-C mutagenesis ofScheffersomyces(formerlyPichia)stipitisNRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

Hughes

Gibbons

Bang

et al. 2012

Journal of Industrial Microbiology and Biotechnology

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Scheffersomyces (formerly Pichia) stipitis NRRL Y-7124 was mutagenized using UV-C irradiation to produce yeast strains for anaerobic conversion of lignocellulosic sugars to ethanol. UV-C irradiation potentially produces large numbers of random mutations broadly and uniformly over the whole genome to generate unique strains. Wild-type cultures of S. stipitis NRRL Y-7124 were subjected to UV-C (234 nm) irradiation targeted at approximately 40% cell survival. When surviving cells were selected in sufficient numbers via automated plating strategies and cultured anaerobically on xylose medium for 5 months at 28°C, five novel mutagenized S. stipitis strains were obtained. Variable number tandem repeat analysis revealed that mutations had occurred in the genome, which may have produced genes that allowed the anaerobic utilization of xylose. The mutagenized strains were capable of growing anaerobically on xylose/glucose substrate with higher ethanol production during 250- to 500-h growth than a Saccharomyces cerevisiae yeast strain that is the standard for industrial fuel ethanol production. The S. stipitis strains resulting from this intense multigene mutagenesis strategy have potential application in industrial fuel ethanol production from lignocellulosic hydrolysates.

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Section: Resultsmentioning

confidence: 99%

Random UV-C mutagenesis ofScheffersomyces(formerlyPichia)stipitisNRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

Hughes

Gibbons

Bang

et al. 2012

Journal of Industrial Microbiology and Biotechnology

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“…Difco Lactobacilli MRS Broth base was manufactured by Becton, Dickinson, and Co. (Sparks, MD). S. cerevisiae strain NRRL Y-2034 was obtained from the ARS Culture Collection maintained at the USDA-ARS National Center for Agricultural Utilization Research (Peoria, IL) (McGhee et al, 1982). Lactobacillus delbrueckii ATCC 4797 was obtained from the American Type Culture Collection (Manassas, VA).…”

Section: Strains and Mediamentioning

confidence: 99%

Modeling bacterial contamination of fuel ethanol fermentation

Bischoff

Liu

Leathers

et al. 2009

Biotech & Bioengineering

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The emergence of antibiotic-resistant bacteria may limit the effectiveness of antibiotics to treat bacterial contamination in fuel ethanol plants, and therefore, new antibacterial intervention methods and tools to test their application are needed. Using shake-flask cultures of Saccharomyces cerevisiae grown on saccharified corn mash and strains of lactic acid bacteria isolated from a dry-grind ethanol facility, a simple model to simulate bacterial contamination and infection was developed. Challenging the model with 10(8) CFU/mL Lactobacillus fermentum decreased ethanol yield by 27% and increased residual glucose from 6.2 to 45.5 g/L. The magnitude of the effect was proportional to the initial bacterial load, with 10(5) CFU/mL L. fermentum still producing an 8% decrease in ethanol and a 3.2-fold increase in residual glucose. Infection was also dependent on the bacterial species used to challenge the fermentation, as neither L. delbrueckii ATCC 4797 nor L. amylovorus 0315-7B produced a significant decrease in ethanol when inoculated at a density of 10(8) CFU/mL. In the shake-flask model, treatment with 2 microg/mL virginiamycin mitigated the infection when challenged with a susceptible strain of L. fermentum (MIC for virginiamycin < or =2 ppm), but treatment was ineffective at treating infection by a resistant strain of L. fermentum (MIC = 16 ppm). The model may find application in developing new antibacterial agents and management practices for use in controlling contamination in the fuel ethanol industry.

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“…al. [30] in order to reduce compaction of the beads. Effluent used for analysis was collected from a sampling port upstream from the reactor.…”

Section: Fermentationsmentioning

confidence: 99%

“…Several reviews have been presented on cell immobilization [24,30]. The value of immobilization is that fermentations can be carried out in a continuous fashion with little cell wash-out.…”

Section: Introductionmentioning

confidence: 99%

Formation of ethanol and higher alcohols by immobilized zymomonas mobilis in continuous culture

Oaxaca

Jones

1991

Acta Biotechnologica

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Cells of Zyrnomonm mobifis ATCC 10988 were immobilized in 1.5% calcium alginate and packed in a column bioreactor for a series of fermentations utilizing 10.0% glucose media with the addition of one of the following amino acids or keto acids: L-leucine, L-isoleucine, L-valine, a-ketoisocaproic acid, a-ketobutyric acid, or a-ketoisovaleric acid. This was done in order to study the rates of production of higher alcohols during ethanolic fermentations at varying dilution rates while under the influence of amino acids or keto acids.Results indicate that the EHRLICH mechanism is operative in Zymomonas sp. a-Ketobutyrate enhanced the production of n-propanol and act-amyl alcohol. a-Ketoisocaproic acid stimulated the production of isoamyl alcohol. a-Ketoisovaleric acid increased the levels of isobutanol. The amino acids also gave rise to their corresponding alcohols but to a far lesser degree than did the keto acids. During high glucose utilization, ethanol yields ranged from 87% to 94% of theoretical with productivity ranging from 60.08 g/l/h in one fermentation (at a dilution rate of 1.35 h-I) to 70.42 g/l/h in another (at a dilution rate of 1.58 h-I). At dilution rates of 1.58 h-', higher alcohol productivity rose to as high as 4,313 mg/l/h in the presence ofa-ketoisocaproic acid, 1,734.49 mg/l/h usinga-ketoisovaleric acid, and 1,618.05 mg/l/h in a-ketobutyric acid. The concomitant production of ethanol and higher alcohols in all of the fermentations indicates that glucose is required for the production of the higher alcohols from their corresponding amino acids or keto acids.

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Ethanol production by immobilized Saccharomyces cerevisiae, Saccharomyces uvarum, and Zymomonas mobilis

Cited by 56 publications

References 10 publications

Random UV-C mutagenesis ofScheffersomyces(formerlyPichia)stipitisNRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

Random UV-C mutagenesis ofScheffersomyces(formerlyPichia)stipitisNRRL Y-7124 to improve anaerobic growth on lignocellulosic sugars

Modeling bacterial contamination of fuel ethanol fermentation

Formation of ethanol and higher alcohols by immobilized zymomonas mobilis in continuous culture

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