Pretreatment process for conversion of cellulose to fuel ethanol
First Claim
1. 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, wherein the feedstock consists of corn, oats, wheat, sugar cane, or a component thereof, wherein the feedstock contains less than 10% starch; and
b. Reacting the selectively bred 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 cellulose 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.
150 Citations
53 Claims
-
1. 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, wherein the feedstock consists of corn, oats, wheat, sugar cane, or a component thereof, wherein the feedstock contains less than 10% starch; and b. Reacting the selectively bred 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)
-
-
13. 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, wherein the feedstock consists of a C4 perennial grass; and b. Reacting the selectively bred 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 (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. 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, wherein the feedstock is corn, oats, wheat, sugar cane, or a component thereof, and wherein the feedstock contains less than 10% starch; and b. Reacting the selectively bred 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 to sugars by using cellulase enzymes; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (27)
-
-
28. 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, wherein the feedstock is a C4 perennial grass; and b. Reacting the selectively bred 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 to sugars by using cellulase enzymes; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (29, 30)
-
-
31. 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, wherein the feedstock consists of corn, wheat, oats, sugar cane, or a component thereof, and wherein the feedstock contains less than 10% starch; and b. Reacting the selectively bred feedstock to 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 (32)
-
-
33. 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, wherein the feedstock consists of a C4 perennial grass; and b. Reacting the selectively bred feedstock to 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 (34, 35)
-
-
36. An improved process for pretreating a lignocellulosic feedstock for conversion 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 is not corn fiber; 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 (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
-
-
49. A process for converting a lignocellulosic feedstock to ethanol, the process 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 0.39, wherein the feedstock is not corn fiber; and b. Reacting the 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 to sugars by using cellulase enzymes; and d. Fermenting the resulting sugars to ethanol; and e. Recovering the ethanol. - View Dependent Claims (50)
-
-
51. A 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, characterized by a ratio of arabinan plus xylan to total nonstarch polysaccharides (AX/NSP) of greater than 0.39, wherein the feedstock is not corn fiber; and b. Reacting the 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 (52, 53)
-
Specification