Yeast strain development for ethanol production
Disclosed herein are yeast strains and derivatives thereof, as well as compositions comprising the yeast strains for use in ethanol manufacture. The disclosure also relates to processes for producing ethanol from biomass using the yeast strains and compositions. In particular, the yeast strains produce lower glycerol and higher ethanol, and have a higher temperature tolerance and higher fermentation rate than strains and products currently used in ethanol production processes.
1 . A Saccharomyces yeast strain wherein:
(i) the yeast strain is selected from the group consisting of:
(a) Saccharomyces strain Y1912, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68003;
(b) Saccharomyces strain Y1913, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68004;
(c) Saccharomyces strain Y1914, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68005;
(d) Saccharomyces strain Y1919, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68006;
(e) Saccharomyces strain Y1923, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68007;
(f) Saccharomyces strain Y1927, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68008; and,
(g) Saccharomyces strain Y1929, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68009; and
(ii) the yeast strain comprise one or more defining characteristics selected from the group consisting of:
(a) a higher ethanol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(b) an increased temperature tolerance compared to Saccharomyces strain Y1609 at a temperature from 32° C. to 36° C.;
(c) a lower glycerol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(d) an increased organic acid tolerance compared to Saccharomyces strain Y1609 at a pH from about 4.0 to about 5.2 in the presence of organic acids; and
(e) an increased fermentation rate compared to Saccharomyces strain Y1609 under the same fermentation conditions.
2 . The yeast strain of claim 1 , wherein the yeast strain:
produces at least about 0.5% more ethanol after 50 hours of fermentation relative to Saccharomyces cerevisiae strain Y1609;
produces at least about 2% less glycerol after 50 hours of fermentation relative to Saccharomyces cerevisiae strain Y1609;
has a fermentation rate that is at least about 2% higher than Saccharomyces cerevisiae strain Y1609 after 24 hours of fermentation; or
a combination thereof.
3 . The yeast strain of claim 1 , wherein the organic acids comprise lactic acid, acetic acid, succinic acid, citric acid, malic acid, fumaric acid, or a combination thereof.
4 . A process for producing ethanol from fermentable a substrate by contacting the fermentable substrate with a fermenting organism, wherein:
(i) the fermenting organism is selected from the group consisting of:
(a) Saccharomyces strain Y1912, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68003;
(b) Saccharomyces strain Y1913, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68004;
(c) Saccharomyces strain Y1914, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68005;
(d) Saccharomyces strain Y1919, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68006;
(e) Saccharomyces strain Y1923, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68007;
(f) Saccharomyces strain Y1927, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68008; and,
(g) Saccharomyces strain Y1929, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68009; and
(ii) the fermenting organism comprises one or more defining characteristics selected from the group consisting of:
(a) a higher ethanol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(b) an increased temperature tolerance compared to Saccharomyces strain Y1609 at a temperature from 32° C. to 36° C.;
(c) a lower glycerol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(d) an increased organic acid tolerance compared to Saccharomyces strain Y1609 at a pH from about 4.0 to about 5.2 in the presence of organic acids; and
(e) an increased fermentation rate compared to Saccharomyces strain Y1609 under the same fermentation conditions.
5 . The process of claim 4 , wherein the fermentable substrate comprises or originates from sugar cane, sugar beet, sweet sorghum, agave, corn, wheat, rice, barley, rye, sorghum, triticale, potato, sweet potato, cassava, or a combination thereof.
6 . The process of claim 4 , wherein the ethanol is used for fuel ethanol, industrial ethanol, potable ethanol, or a combination thereof.
7 . The process of claim 4 , wherein the fermentable substrate for producing the ethanol is a starch or a sugar.
8 . The process of claim 7 , wherein simultaneous saccharification and fermentation (SSF), batch fermentation, separate hydrolysis and fermentation (SHF), or continuous fermentation is used to produce the ethanol.
9 . A composition comprising the yeast strain of claim 1 and one or more components selected from surfactants, emulsifiers, gums, swelling agents, protectants, and antioxidants, wherein the composition comprises one or more defining characteristics selected from the group consisting of:
(a) a higher ethanol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(b) an increased temperature tolerance compared to Saccharomyces strain Y1609 at a temperature from 32° C. to 36° C.;
(c) a lower glycerol yield than Saccharomyces strain Y1609 under same fermentation conditions;
(d) an increased organic acid tolerance compared to Saccharomyces strain Y1609 at a pH from about 4.0 to about 5.2 in the presence of organic acids; and
(e) an increased fermentation rate compared to Saccharomyces strain Y1609 under the same fermentation conditions.
10 . A process for producing ethanol from a biomass by contacting the biomass with the composition of claim 9 .
11 . The process of claim 10 , wherein the ethanol is used for fuel ethanol, industrial ethanol, potable ethanol, or a combination thereof.
12 . The process of claim 10 , wherein the ethanol is produced using a starch or a sugar.
13 . The process of claim 12 , wherein simultaneous saccharification and fermentation (SSF), batch fermentation, separate hydrolysis and fermentation (SHF), or continuous fermentation is used to produce the ethanol.
14 . A method of producing a fermentation product from a fermentable substrate by contacting the fermentable substrate with a fermenting organism, wherein the fermenting organism is selected from the group consisting of:
(a) Saccharomyces strain Y1912, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68003;
(b) Saccharomyces strain Y1913, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68004;
(c) Saccharomyces strain Y1914, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68005;
(d) Saccharomyces strain Y1919, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68006;
(e) Saccharomyces strain Y1923, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68007;
(f) Saccharomyces strain Y1927, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68008; and,
(g) Saccharomyces strain Y1929, a representative sample of the strain having been deposited under NRRL Patent Deposit Designation No. Y-68009.
15 . The method of claim 14 , wherein the fermentable substrate comprises or originates from sugar cane, sugar beet, sweet sorghum, agave, corn, wheat, rice, barley, rye, sorghum, triticale, potato, sweet potato, cassava, or a combination thereof.
16 . The method of claim 14 , wherein the fermentation product is ethanol, and the ethanol is used for fuel ethanol, industrial ethanol, potable ethanol, or a combination thereof.
17 . The method of claim 14 , wherein batch fermentation, continuous fermentation, simultaneous saccharification and fermentation (SSF), or separate hydrolysis and fermentation (SHF) is used to produce the fermentation product.