Pretreatment process for conversion of cellulose to fuel ethanol
First Claim
1. An improved process for pretreating a lignocellulosic feedstock intended to be converted to fuel ethanol, consisting essentially of the following steps:
- a. Choosing a feedstock comprised of at least hemicellulose and cellulose, and characterized by a ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) that is greater than 0.39, wherein the feedstock consists of oat hulls or corn cobs; and
b. Reacting the chosen feedstock at conditions which disrupt its fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes.
3 Assignments
0 Petitions
Accused Products
Abstract
An improved pretreatment of cellulosic feedstocks, to enable economical ethanol production by enzyme treatment. The improved pretreatment comprises choosing either a feedstock with a ratio of arabinoxylan to total nonstarch polysaccharides (AX/NSP) of greater than about 0.39, or a selectively bred feedstock on the basis of an increased ratio of AX/NSP over a starting feedstock material, and reacting at conditions that disrupt the fiber structure and hydrolyze a portion of the cellulose and hemicellulose. This pretreatment produces a superior substrate for enzymatic hydrolysis, by enabling the production of more glucose with less cellulase enzyme than any known procedures. This pretreatment is uniquely suited to ethanol production. Preferred feedstocks with an AX/NSP level greater than about 0.39 include varieties of oat hulls and corn cobs.
-
Citations
58 Claims
-
1. An improved process for pretreating a lignocellulosic feedstock intended to be converted to fuel ethanol, consisting essentially of the following steps:
-
a. Choosing a feedstock comprised of at least hemicellulose and cellulose, and characterized by a ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) that is greater than 0.39, wherein the feedstock consists of oat hulls or corn cobs; and b. Reacting the chosen feedstock at conditions which disrupt its fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. An improved process for converting a lignocellulosic feedstock to ethanol, consisting essentially of the following steps:
-
a. Choosing a feedstock comprised of at least hemicellulose and cellulose, and characterized by a ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) that is greater than about 0.39, wherein the feedstock consists of oat hulls or corn cobs; and b. Reacting the chosen feedstock at conditions which disrupt its fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; and c. Hydrolyzing the pretreated feedstock by using cellulase enzymes; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. An improved process for converting a lignocellulosic feedstock to glucose, consisting essentially of the following steps:
-
a. Choosing a feedstock comprised of at least hemicellulose and cellulose, and characterized by a ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) of greater than about 0.39, wherein the feedstock consists of corn cobs or oat hulls; and b. Reacting the chosen feedstock at conditions which disrupt its fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; and c. Hydrolyzing at least 40% of the cellulose in the pretreated feedstock to glucose by using cellulase enzymes. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. An improved process for pretreating a lignocellulosic feedstock for conversion to fuel ethanol, consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting material to a level greater than about 0.39; and b. Reacting the selectively bred feedstock at an average temperature of 180°
C. to 270°
C., at pH 0.5 to 2.5, for a period of 5 seconds to 60 minutes to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes. - View Dependent Claims (36, 42)
-
-
37. An improved process for pretreating a lignocellulosic feedstock for conversion to fuel ethanol, consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting feedstock material to a level that is greater than about 0.39; and b. Reacting the selectively bred feedstock in two stages, with the first stage at an average temperature below 180 C. and the second stage at an average temperature above 180 C. to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes. - View Dependent Claims (38, 39, 40, 41)
-
-
43. A process for converting a lignocellulosic feedstock to ethanol, the process consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting feedstock material to a level that is greater than about 0.39; and b. Reacting the selectively bred feedstock at an average temperature of 180°
C. to 270°
C., at pH 0.5 to 2.5, for a period of 5 seconds to 60 minutes to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; andc. Hydrolyzing the pretreated feedstock to sugars by using cellulase enzymes at a dosage of 1.0 to 10.0 filter paper units (FPU) of cellulase enzyme per gram of cellulose; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (44, 50)
-
-
45. A process for converting a lignocellulosic feedstock to ethanol, the process consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting feedstock material to a level that is greater than about 0.39; and b. Reacting the chosen feedstock in two stages, with the first stage at an average temperature below 180°
C. and the second stage at an average temperature above 180 C. to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; andc. Hydrolyzing the pretreated feedstock to sugars by using cellulase enzymes at a dosage of 1.0 to 10.0 filter paper units (FPU) of cellulase enzyme per gram of cellulose; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (46, 47, 48, 49)
-
-
51. A process for converting a lignocellulosic feedstock to glucose, consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting feedstock material to a level that is greater than about 0.39; and b. Reacting the selectively bred feedstock at an average temperature of 180°
C. to 270°
C., at a pH of 0.5 to 2.5, for a period of 5 seconds to 60 minutes to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; andc. Hydrolyzing at least 40% of the cellulose in the pretreated feedstock to glucose by using cellulase enzymes at a dosage of 1.0 to 10.0 filter paper units (FPU) of cellulase enzyme per gram of cellulose. - View Dependent Claims (52, 58)
-
-
53. A process for converting a lignocellulosic feedstock to glucose, consisting essentially of the following steps:
-
a. Choosing a selectively bred feedstock, comprised of at least hemicellulose and cellulose, on the basis of an increased ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) over a starting feedstock material to a level greater than about 0.39; and b. Reacting the selectively bred feedstock in two stages, with the first stage at an average temperature below 180°
C. and the second stage at an average temperature above 180 C. to disrupt the fiber structure and effect an hydrolysis of a portion of the hemicellulose and cellulose, in order to create a pretreated feedstock with increased accessibility to being digested, during a treatment with cellulase enzymes; andc. Hydrolyzing at least 40% of the cellulose in the pretreated feedstock to glucose by using cellulase enzymes at a dosage of 1.0 to 10.0 filter paper units (FPU) of cellulase enzyme per gram of cellulose. - View Dependent Claims (54, 55, 56, 57)
-
Specification