Progress 01/01/07 to 12/31/07
Outputs
Sorghum is a major cereal crop in the U.S. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The major barriers limiting the industrial use of sorghum are poor wet-milling properties and relatively low enzymatic degradation in a typical dry-mill process. The goal of this research is to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus is to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model to quantify and prioritize the saving potential from factors identified in this research. The research included the selection of seventy sorghum genotypes and elite hybrids with a broad range of chemical compositions and physical properties from among 1200 breeding lines. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific
attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. The key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, formation of amylose-lipid complex in the mass, etc. Results showed that ethanol fermentation efficiency increased as the ratio of amylose to amylopectin decreased, and waxy sorghum yielded relative higher fermentation efficiencies. Ethanol yield and fermentation efficiency increased as protein digestibility and extractable protein increased. Mash viscosity, level of phenolic compounds, and the formation of an amylose-lipids complex had a negative effect on ethanol fermentation. In addition
to genotype, growing location and irrigation also had a significant effect on ethanol fermentation efficiency and yield. Major characteristics of an elite sorghum genotype for the bioconversion process include high starch content (high yields), rapid liquefaction, low viscosity during liquefaction, fast fermentation speed, and high bioconversion rate. Analysis of the chemical composition of distiller's dry grains with solubles (DDGS) from sorghum lines with extremely high and low ethanol fermentation efficiency showed that the residual starch in the DDGS was mostly resistant starch associated with amylose and in forms of lipid-amylose complex. Commercial sorghum ethanol producers were contacted to gain actual practical information and data on processing parameters and energy utilization, throughout the commercial process. We developed a platform Energy Life Cycle Analysis Model (ELCAM) with a base case that showed a net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used
to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2MM Btu/ac.
Impacts
The results from this research will allow more focused development and improvement of processing methods based on knowledge of how particular grain properties impact bioconversion to commercial products. With confirmation of the key impact factors found in our research, it is envisaged that the utilization of processed sorghum for industrial uses could be increased. Although fermentable starch has recently received growing attention as a valuable trait in corn, the concept was less well understood in sorghum. For the first time, this concept has now been explored in sorghum and important initial information linking genetics-grain structure-grain composition-conversion has been provided. Application of the research findings to the bioprocessing of sorghum grain, could benefit both grain producers and the bio-industry via the following areas: (1) approaches and capabilities to improve the efficiency of sorghum processing; (2) improvement in sorghum conversion yield to
industrial products, thereby improving sorghum economics; (3) information to assist in the development of new and improved sorghum hybrids; and (4) enhancement of economic rural development through expanded sorghum production, especially across the many drier sorghum-growing States.
Publications
- 1. D.Y. Corredor, S.R Bean, T. Schober, and D. Wang. 2006. Effect of decorticating sorghum on ethanol production and DDGS quality. Cereal Chemistry 83(1):17-21 2. X. Wu, R. Zhao, D. Wang, S.R. Bean, P.A. Seib, M. Tuinstra, M. Campbell, and A. OBrien. 2006. Effects of amylose amylopectin ratio, corn protein and corn fiber contents on ethanol production. Cereal Chemistry 83(5):569-575 3. X. Wu, R. Zhao, S.R. Bean, P.A. Seib, J.S. McLaren, R.L. Madl, M. Tuinstra , M. C. Lenz, and D. Wang. 2006. Factors impacting ethanol production from grain sorghum in dry-grind process. Cereal Chemistry 84(2):130-136.
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Progress 09/01/04 to 08/31/07
Outputs
OUTPUTS: Sorghum is a major cereal crop in the U.S. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The major barriers limiting the industrial use of sorghum are poor wet-milling properties and relatively low enzymatic degradation in a typical dry-mill process. The goal of this research is to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus is to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model to quantify and prioritize the saving potential from factors identified in this research. The research included the selection of seventy sorghum genotypes and elite hybrids with a broad range of chemical compositions and physical properties from among 1200 breeding lines. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. The key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylase to amylopectin, formation of amylase-lipid complex in the mass, etc. Results showed that ethanol fermentation efficiency increased as the ratio of amylose to amylopectin decreased, and waxy sorghum yielded relative higher fermentation efficiencies. Ethanol yield and fermentation efficiency increased as protein digestibility and extractable protein increased. Mash viscosity, level of phenolic compounds, and the formation of an amylase-lipids complex had a negative effect on ethanol fermentation. In addition to genotype, growing location and irrigation also had a significant effect on ethanol fermentation efficiency and yield. Major characteristics of an elite sorghum genotype for the bioconversion process include high starch content (high yields), rapid liquefaction, low viscosity during liquefaction, fast fermentation speed, and high bioconversion rate. Analysis of the chemical composition of distiller's dry grains with solubles (DDGS) from sorghum lines with extremely high and low ethanol fermentation efficiency showed that the residual starch in the DDGS was mostly resistant starch associated with amylose and in forms of lipid-amylose complex. Commercial sorghum ethanol producers were contacted to gain actual practical information and data on processing parameters and energy utilization, throughout the commercial process. We developed a platform Energy Life Cycle Analysis Model (ELCAM) with a base case that showed a net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2MM Btu/ac. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results from this research will allow more focused development and improvement of processing methods based on knowledge of how particular grain properties impact bioconversion to commercial products. With confirmation of the key impact factors found in our research, it is envisaged that the utilization of processed sorghum for industrial uses could be increased. Although fermentable starch has recently received growing attention as a valuable trait in corn, the concept was less well understood in sorghum. For the first time, this concept has now been explored in sorghum and important initial information linking genetics-grain structure-grain composition-conversion has been provided. Application of the research findings to the bioprocessing of sorghum grain, could benefit both grain producers and the bio-industry via the following areas: (1) approaches and capabilities to improve the efficiency of sorghum processing; (2) improvement in sorghum conversion yield to industrial products, thereby improving sorghum economics; (3) information to assist in the development of new and improved sorghum hybrids; and (4) enhancement of economic rural development through expanded sorghum production, especially across the many drier sorghum-growing States.
Publications
- 1. D.Y. Corredor, S.R. Bean, T. Schober, and D. Wang. 2006. Effect of decorticating sorghum on ethanol production and DDGS quality. Cereal Chemistry 83(1):17-21.
- 2. X. Wu, R. Zhao, D. Wang, S.R. Bean, P. A. Seib, M. Tuinstra, M. Campbell, and A. OBrien. 2006. Effects of amylose amylopectin ratio, corn protein and corn fiber contents on ethanol production. Cereal Chemistry 83(5):569-575.
- 3. X. Wu, R. Zhao, S.R. Bean, P.A. Seib, J.S. McLaren, R.L. Madl, M. Tuinstra, M.C. Lenz, and D. Wang. 2006. Factors impacting ethanol production from grain sorhum in dry-grind process. Cereal Chemistry 84(2):130-136.
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Progress 01/01/06 to 12/31/06
Outputs
The goal of this research is to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus is to understand the relationship among genetics-structure-function-conversion and the key factors impacting bioprocessing to selected products (ethanol and lactic acid), as well as to develop an energy life cycle analysis model to quantify and prioritize the saving potential from factors identified in this research. During the past year progress has been made in developing a coordinated understanding of the relationships among composition, chemical structure, physical features, and available/usable-stored starch (objective 2); integrating these findings to determine the impact of compositional, structural, and physical factors and the key interactions on fermentation yields from sorghum grain (objective 4); and updating our energy life cycle analysis model (ELCAM) (objective 5). The ethanol fermentation results from seventy
sorghum genotypes and elite hybrids have been used to determine the impact of compositional, structural, and physical factors and to identify the key interactions impacting ethanol yield from sorghum grain. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of grain sorghum were identified. In general, ethanol yield increased as starch content increased. However, there is no linear relationship between starch content and fermentation efficiency. The key factors affecting the ethanol fermentation efficiency of grain sorghum include protein digestibility, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, formation of amylose-lipid complex in the mass, etc. Results showed that ethanol fermentation efficiency increased as the ratio of amylose to amylopectin decreased, and waxy sorghum yielded relatively higher
fermentation efficiencies. Ethanol yield and fermentation efficiency increased as protein digestibility and extractable protein increased. Mash viscosity, level of phenolic compounds, and the formation of amylose-lipids complex had a negative effect on ethanol fermentation. Analysis of the chemical composition of distiller's dry grains with solubles (DDGS) from sorghum lines with extremely high and low ethanol fermentation efficiency showed that the residual starch in the DDGS are mostly resistant starchs associated with amylose and in forms of lipid-amylose complex. Commercial sorghum ethanol producers were contacted to gain actual practical information and data on processing parameters and energy utilization, throughout the commercial process. The ELCAM for sorghum has been updated to provide a realistic platform baseline. The experimental findings from the research are being applied to the ELCAM to determine the potential savings for selected factors.
Impacts
The results from this research will allow testing of hypotheses concerning the impact of particular grain properties on the bioconversion to commercial products. Assuming success, and identification of the key factors affecting bioconversion, it is envisaged that the utilization of processed sorghum for industrial uses will increase substantially. Although fermentable starch has recently received growing attention as a valuable trait in corn, the concept is less understood in sorghum. Indeed, such genetic-structure-function-conversion analyses as proposed have never been performed for grain sorghum and may lead to significant breakthroughs for utilization via improved bioprocessing. In addition, the results from this research would benefit both grain producers and the bio-industry and lead to (1) capabilities to improve the efficiency of sorghum processing; (2) improvement in sorghum conversion yield to industrial products; (3) information to assist in the development
of new and improved sorghum hybrids; and (4) enhancement of economic rural development, especially across the many sorghum-growing states.
Publications
- X. Wu, R. Zhao, D. Wang, S.R. Bean, P.A. Seib, M. Tuinstra, M. Campbell, and A. OBrien. 2006. Effects of amylose amylopectin ratio, corn protein and corn fiber contents on ethanol production. Cereal Chemistry 83(5):569-575.
- X. Wu, R. Zhao, S.R. Bean, P.A. Seib, J.S. McLaren, R.L. Modl, M. Tuinstra , M. C. Lenz, and D. Wang. 2006. Factors impacting ethanol production from grain sorghum in dry-grind process. Cereal Chemistry (In press).
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Progress 01/01/05 to 12/31/05
Outputs
The goal of this research is to improve bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus is to understand the relationship among genetics-structure-function-conversion and the key factors impacting bioprocessing to selected products (ethanol and lactic acid), as well as to develop an energy life cycle analysis model to quantify and prioritize the saving potential from factors identified in this research. During the past year progress has been made in developing a coordinated understanding of the relationship among composition, chemical structure, physical features, and available/usable-stored starch (objective 2); expanding a demonstrated micro-fermentation system to allow higher throughput screening of test samples and conditions for production of ethanol and lactic acid (objective 3); and creating an initial energy life cycle analysis model to quantify and prioritize the savings potential from factors identified in
this research based on both energy and economics (objective 5). Seventy sorghum genotypes and elite hybrids with a broad range of chemical compositions and physical properties have been evaluated for ethanol production and used to study the relationship among composition, chemical structure, physical features, and available/usable starch on ethanol fermentation efficiency. Genotype had a significant effect on final production yield and fermentation efficiency. Variations of 22% in ethanol yield and 7% in fermentation efficiency were observed among the 70 sorghum samples. Genetic lines with extremely high and low bioconversion rates and some specific attributes that may be manipulated to improve the bioconversion rate of grain sorghum were identified. Major characteristics of an elite sorghum genotype for the bioconversion process include high starch content (high yields), quick liquefaction, low viscosity during liquefaction, high fermentation speed, and high bioconversion rate. Major
factors affecting the bioconversion rate of grain sorghum are phenol compounds, tight-storage protein matrix, low-protein digestibility, high viscosity, and high-gelatinization temperature. Results from decorticated sorghum showed that removal of phenol compounds can significantly increase liquefaction speed, reduce the viscosity of sorghum mash, and increase the bioconversion rate. Study of the effects and interactions of the ratio of amylose to amylopectin, protein content, and fiber content on the bioconversion rate showed that ethanol fermentation efficiency decreased when amylose content was above 30%. A basic platform energy life cycle analysis model has been generated to allow comparative evaluation of functional differences in feedstock or processes in terms of energy impact in the production of ethanol. A draft model has been created to evaluate the impact of feedstock and process differences on the economic aspects of ethanol production from sorghum.
Impacts
The results from this research will allow testing of hypotheses concerning the impact of particular grain properties on the bioconversion to commercial products. Assuming success, and identification of the key factors affecting bioconversion, it is envisaged that the utilization of processed sorghum for industrial uses will increase substantially. Although fermentable starch has recently received growing attention as a valuable trait in corn, the concept is less well understood in sorghum. Indeed, such genetic-structure-function-conversion analyses as proposed have never been performed for grain sorghum and may lead to significant breakthroughs for utilization via improved bioprocessing. In addition, the results from this research would benefit both grain producers and the bio-industry and lead to (1) capabilities to improve the efficiency of sorghum processing; (2) improvement in sorghum conversion yield to industrial products; (3) information to assist in the
development of new and improved sorghum hybrids; and (4) enhancement of economic rural development, especially across the many sorghum-growing States.
Publications
- D.Y. Corredor, S.R Bean, T. Schober, and D. Wang. 2005. Effect of decorticating sorghum on ethanol production and DDGS quality. Cereal Chemistry (In press).
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Progress 09/01/04 to 12/31/04
Outputs
Sorghum is a major cereal crop in the United States. While some 5 percent of sorghum is used for processing to ethanol, sorghum appears to have been underutilized as a renewable feedstock for value-added products and industrial applications. The major barriers limiting the industrial use of sorghum are poor wet-milling properties and relatively low enzymatic degradation in a typical dry-mill process. The goal of this research is to improve the efficiency of production of biofuels and biobased products based on processed sorghum. The main focus is to understand the relationship among genetic-structure-function-conversion and the key factors impacting the bioprocessing to selected products (ethanol and lactic acid). Seventy sorghum genotypes and elite hybrids with a broad range of chemical compositions and physical properties have been selected for this research from 1200 breeding lines. The criteria for the genotype selection were based on variability in breeding
background, phenotypic plant type, and end-use purpose. Special attention was paid to grain traits such as protein content, starch content, ratio of amylose and amylopectin, oil content, phenolic compound such as tannin content, kernel color, kernel hardness, and kernel size. These sorghum genotypes and hybrids have been planted in Puerto Rico in November and will be harvested by early April, 2005. The large sample set evaluation and integrated results analyse will be conducted on the selected seventy sorghum genotypes. In the meanwhile, several research projects have been conducted. A system calibration study has been conducted to reduce the fermentation variation and to increase repeatability for the subsequent experimental studies; a model study examined the effects and interactions of the ratio of amylose to amylopectin, protein content, and fiber content on bioconversion rate and final product yields using purified starch, protein, and fiber as well as selected cereal grains with
a large range of the ratio of amylose to amylopectin; pretreatment technologies such as extrusion and steeping have been used to study the effect of chemical structure, especially the interaction of starch and protein, on bioconversion rate and final product yield; and the information collection and literature review have been conducted for development of energy life cycle analysis model. As research results, two abstracts have been submitted for a technical meeting.
Impacts
The results from this research will allow testing of hypotheses concerning the impact of particular grain properties on the bioconversion to commercial products. Assuming success, and identification of the key factors affecting bioconversion, it is envisaged that the utilization of processed sorghum for industrial uses will increase substantially. Although fermentable starch has recently received growing attention as a valuable trait in corn, the concept is less well understood in sorghum. Indeed, such genetic-structure-function-conversion analyses as proposed have never been performed for grain sorghum and may lead to significant breakthroughs for utilization via improved bioprocessing. In addition, the results from this research would benefit both grain producers and the bio-industry and lead to (1) capabilities to improve the efficiency of sorghum processing; (2) improvement in sorghum conversion yield to industrial products; (3) information to assist in the
development of new and improved sorghum hybrids; and (4) enhancement of economic rural development, especially across the many sorghum-growing States.
Publications
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