Efficient fermentation of Pinus sp. acid hydrolysates by an ethanologenic strain of Escherichia coli

Barbosa, M.F.S.; Beck, Mary Jim; Fein, Jared E.; Potts, D; Ingram, L. O.

doi:10.1128/aem.58.4.1382-1384.1992

Cited by 84 publications

(14 citation statements)

References 18 publications

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“…In a recent study comparing the fermentation performance of different microorganisms in a pentose-rich acid hydrolysate of corn cob, it was concluded that recombinant Escherichia coli K O l l is currently the best known pentose-fermenting organism . E. coli KOll ferments monosaccharides with high yield and productivity of ethanol, but in some cases the microorganism suffers from inhibition (Barbosa et al, 1992;Lawford and Rousseau, 1993;Olsson et al, 1994). It is possible to increase the fermentability of the sugar solutions by various detoxification methods, such as ion exchange (Clark and Mackie, 19841, calcium hydroxide treatment (Leonard and Hajny, 1945), molecular sieves (Tran and Chambers, 19861, and steam stripping (Yu et al, 19871, but at an additional cost.…”

Section: Introductionmentioning

confidence: 99%

Cost Analysis of Ethanol Production from Willow Using Recombinant Escherichia coli

Sivers

Zacchi²,

Olsson

et al. 1994

Biotechnology Progress

160

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This study comprises a technical and economic analysis of the production of fuel ethanol by fermentation of a pentose-rich hydrolysate with recombinant Escherichia coli, strain KO11. Hydrolysate from steam-pretreated willow was used as raw material in calculations regarding the fermentation. The calculations were based on a feed capacity of 10 metric tons of dry willow per hour to the pretreatment stage, providing 35 metric tons of hydrolysate per hour, consisting of 45 g of sugars/L, to the pentose fermentation plant. A detoxification step was included, since the hydrolysate has been shown to have an inhibitory effect on the E. coli KO11. The technical data used in the calculations were based on a kinetic fermentation model, which was developed from laboratory-scale experiments in a previous study. The economic analysis predicted an ethanol production cost of 48/L in the pentose fermentation plant, indicating potentially good economy. The detoxification cost constitutes 22% of this cost. Sensitivity analyses revealed that if the concentration of sugars in the feed to the fermentation was decreased by 40% to 27 g/L, the ethanol production cost was increased to 54/L. The production cost was increased to 50/L ethanol if the cell mass was recirculated to the fermentation stage 5 times instead of 20.

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Section: Introductionmentioning

confidence: 99%

Cost Analysis of Ethanol Production from Willow Using Recombinant Escherichia coli

Sivers

Zacchi²,

Olsson

et al. 1994

Biotechnology Progress

160

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“…Exposed cellulose fibers are then hydrolyzed with strong acids or by enzymes to produce a soluble sugar solution which can be fermented to ethanol. Pentose and hexose sugars generated from an initial hydrolysis of hemicellulose can also be fermented to ethanol (Barbosa et al, 1992;Beall et al, 1992;Jeffries, 1988). Burning unsaccharified carbohydrate plus lignin could provide sufficient energy for ethanol recovery (Kerstetter and Lyons, 1991).…”

Section: Introductionmentioning

confidence: 99%

Fermentation of Crystalline Cellulose to Ethanol by Klebsiella oxytoca Containing Chromosomally Integrated Zymomonas mobilis Genes

Doran

Ingram

1993

Biotechnology Progress

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Complete enzymatic hydrolysis of cellulose to glucose is generally required for efficient fermentation to ethanol. This hydrolysis requires endoglucanase, exoglucanase, and cellobiase. The Gram‐negative bacterium, Klebsiella oxytoca, contains the native ability to transport and metabolize cellobiose, minimizing the need for extracellular cellobiase. Strain P2 is a recombinant derivative in which the Zymomonas mobilis pdc and adhB genes have been integrated into the chromosome and expressed, directing the metabolism of pyruvate to ethanol. This organism has been evaluated in simultaneous sacchari‐fication and fermentation (SSF) experiments to determine optimal conditions and limits of performance. The temperature was varied between 32 and 40 °C over a pH range of 5.0–5.8 with 100 g/L crystalline cellulose (Sigmacell 50, Sigma Chemical Company, St. Louis, MO) as the substrate and commercial cellulase (Spezyme CE, South San Francisco, CA). A broad optimum for SSF was observed, with a pH of 5.2–5.5 and temperatures of 32–35 °C, which allowed the production of over 44 g of ethanol/L (81–86% of the maximum theoretical yield). Although the rate of ethanol production increased with cellulase, diminishing improvements were observed at enzyme loadings above 10 filter paper units/g of cellulose. Over 40 g of ethanol/L was produced with relatively low enzyme loadings: 7–10 filter paper units/g of cellulose. Two optimal SSF conditions were identified for fermentation yield with strain P2: pH 5.2 at 35 °C and pH 5.5 at 32 °C. Under these conditions, 47 g of ethanol/L was produced in 144 h (0.48 g of ethanol/g of cellulose). Maximal rates of ethanol production were observed at 37 °C and pH 5.0 and produced over 40 g of ethanol/L in 72 h (final yield of 0.432 g of ethanol/g of cellulose after 96 h). All fermentations except those conducted at 40 °C and low pH (pH 5.0–5.5) exceeded 70% of theoretical ethanol yields. Tight process controls may not be required using this organism since temperatures between 32 and 37 °C at pH ranges between 5.0 and 5.8 still produced good yields.

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“…Lignocellulose is a complex polymer (15,23) composed of cellulose, hemicellulose, and lignin. In previous studies, recombinant Escherichia coli (2,3,20,21,26,32) and Klebsiella oxytoca (8,34) containing Zymomonas mobilis genes which efficiently ferment both hexose and pentose sugars have been developed for ethanol production. In E. coli, plasmid-borne constructs have been replaced by strains in which the Z. mobilis genes have been integrated into the chromosome to maximize stability (33).…”

mentioning

confidence: 99%

Ethanol production from cellobiose, amorphous cellulose, and crystalline cellulose by recombinant Klebsiella oxytoca containing chromosomally integrated Zymomonas mobilis genes for ethanol production and plasmids expressing thermostable cellulase genes from Clostridium thermocellum

Wood

Ingram

1992

Appl Environ Microbiol

Self Cite

132

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The Zymomonas mobilis genes for ethanol production have been integrated into the chromosome ofKlebsiella oxytoca M5A1. The best of these constructs, strain P2, produced ethanol efficiently from cellobiose in addition to monomeric sugars. Utilization of cellobiose and cellotriose by this strain eliminated the requirement for external 1-glucosidase and reduced the amount of commercial cellulase needed to ferment Solka Floc SW40 (primarily crystalline cellulose). The addition of plasmids encoding endoglucanases from Clostridium thermocelum resulted in the intracellular accumulation of thermostable enzymes as coproducts with ethanol during fermentation. The best of these, strain P2(pCT603T) containing celD, was used to hydrolyze amorphous cellulose to cellobiose and produce ethanol in a two-stage process. Strain P2(pCT603T) was also tested in combination with commercial cellulases. Pretreatment of Solka Floc SW40 at 60°C with endoglucanase D DH5ot lacZM15 recA Bethesda Research Laboratories KO11 fd Cmr IPETF 33 K oxytoca M5A1 Prototrophic 34 M5A1(pLOI555) Cmr PETb 34 M5A1 Sic Cmr IPET This study S2 Cmr IPET This study S3 Cmr IPET This study P1 Cmr IPET This study P2 Cmr IPET This study Bi Cmr IPET This study Plasmids pCOS2EMBL Tcr 38 pLOI510 Cmr PET 34 pCT105 Apr cel + 12 pCr207 Apr celB+ 23 pCT301 Apr Tcr celC+ 37 pCT603 Apr Tcr celD+ 24 pCT1O5T Apr Tcr cel4A+ This study pCT207T Apr Tcr celB+ This study pCT603T Apr Tcr celD+ This study a IPET refers to the integration of Z. mobilis pdc and adhB genes into the chromosome. b PET refers to the presence of Z. mobilis pdc and adhB genes on plasmid pLOI555. c S1, S2, S3, P1, P2, and Bi refer to strains derived from independent integration events by using Sall, PstI, or BamHI DNA fragments from pLOI510 as the source of pdc, adhB, and cat.

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Efficient fermentation of Pinus sp. acid hydrolysates by an ethanologenic strain of Escherichia coli

Cited by 84 publications

References 18 publications

Cost Analysis of Ethanol Production from Willow Using Recombinant Escherichia coli

Cost Analysis of Ethanol Production from Willow Using Recombinant Escherichia coli

Fermentation of Crystalline Cellulose to Ethanol by Klebsiella oxytoca Containing Chromosomally Integrated Zymomonas mobilis Genes

Ethanol production from cellobiose, amorphous cellulose, and crystalline cellulose by recombinant Klebsiella oxytoca containing chromosomally integrated Zymomonas mobilis genes for ethanol production and plasmids expressing thermostable cellulase genes from Clostridium thermocellum

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