Patent DE913892C successfully refreshed from Google Patents.
US4477569A
Expired / Lapsed
US
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Pentose fermentation with selected yeast
Assignee: National Research Council Canada
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Filing: 1982-02-18
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Granted: 1984-10-16
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Expires: 2002-02-18
Abstract
Abstract It has been found possible to ferment the pentose D-xylose directly to ethanol with the selected yeast Pachysolen tannophilus. At least an initial aerobic stage is desirable. Improved yields have been obtained when the yeast cells are recycled continually at high cell densities. Fermentation of D-galactose and other hexoses along with D-xylose has been found possible with selected strains or mutants.
Inventors
- 👤 Henry Schneider
- 👤 Ryszard Maleszka
- 👤 Patrick Y. Wang
- 👤 Ivan A. Veliky
- 👤 Yui-Kwok Chan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:21
CPC Classifications
C; C12; C12P; C12P7/00; C12P7/02; C12P7/04; C12P7/06; C12P7/065; Y; Y02; Y02E; Y02E50/00; Y02E50/10; Y10; Y10S; Y10S435/00; Y10S435/8215; Y10S435/911
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A method of producing ethanol directly from a substrate comprising D-galactose and D-xylose, which comprises: (a) screening and selecting Pachysolen tannophilus having the identifying characteristics of NRCC-PTXG-1 or mutants thereof which can ferment at least said two sugars to ethanol, concurrently, (b) inoculating a growth-supporting medium containing said substrate with the selected mutant, (c) providing access of air or oxygen to the medium at least for an initial stage, (d) allowing growth and accumulation of ethanol to occur, (e) separating the medium from the yeast cells and recovering ethanol, and (f) recycling the yeast cells to ferment fresh medium in (b).
Claim 2
Independent Claim
101 words
A method of producing ethanol directly from a substrate comprising D-galactose and D-xylose, which comprises: (a) screening and selecting Pachysolen tannophilus having the identifying characteristics of NRCC-PTXG-1 or mutants thereof which can ferment at least said two sugars to ethanol, concurrently, (b) inoculating a growth-supporting medium containing said substrate with the selected mutant, (c) providing access of air or oxygen to the medium at least for an initial stage, (d) allowing growth and accumulation of ethanol to occur, (e) separating the medium from the yeast cells and recovering ethanol, and (f) recycling the yeast cells to ferment fresh medium in (b).
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the cells are separated and recycled continually.
Claim 4
Dependent Claim
22 words
The method of claim 2 wherein ethanol is recovered from media fermented with recycled cells until the highest ethanol concentration is achieved.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein the cells being recycled are immobilized.
Claim 6
Dependent Claim
17 words
The method of claim 4 wherein the cells are immobilized in a gel of the alginate type.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the cells are separated and recycled at about 24 hour intervals.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the fermentation temperature is about 30°-37° C.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein the fermentations for ethanol production are run aerobically for the first 4-8 hours, and anaerobically for the remainder of the fermentations.
Claim 10
Dependent Claim
23 words
The method of claim 8 wherein the cell densities are above about 7.5 mg dry wt. per ml of culture for ethanol production.
Claim 11
Dependent Claim
13 words
The method of claim 1 wherein the substrate comprises a spent sulfite liquor.
References Cited (Backward Citations)
US4102745A
Cited
US4359534A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |