University of Kentucky
In Vitro Starch Catabolism, a Novel, Environmentally Safe Means of Starch Processing.
Institution
University of Kentucky
Faculty Advisor/ Mentor
Matthew Gentry
Abstract
Starch is a key component in many aspects of daily life, including nutrition, biofuel production, and industrial processing: 50-80% of daily caloric intake comes from starch; >20% of corn starch produced in the U.S. is converted to ethanol; and starch is a cheap and renewable industrial feedstock for producing paper, textiles, adhesives, plastics, and pharmaceuticals. However, starch is difficult to manipulate during industrial processing because it is insoluble in water. Current means of starch processing involves harsh chemicals and present environmental concerns. Starch-based feedstocks are generated using physical, chemical and enzymatic methods. Physical methods include cyclic heating/cooling between 50°C and >100°C. The addition of acids and bases to this process breaks down starch and converts starch to a structure that is more amenable to further processing. Lastly, an enzyme called amylase is utilized to break starch down into simple sugars (i.e. table sugar). Plants synthesize starch every 24 hours during daylight as a means to store energy captured from the sun. Plants then break down starch at night and utilize this stored energy cache. Clearly, plants do not use harsh chemicals or extreme temperatures to break down starch. Instead, they utilize a cyclic system of three classes of enzymes to break down starch: kinases, amylases, and phosphatases. Our lab is exploring how these enzymes break down starch, defining their properties, and optimizing how these enzymes work. To date, most of the work on the proteins from this system has been done using a standard laboratory model organism that is not agriculturally relevant. Therefore, I chose to study these proteins from agriculturally relevant organisms: potatoes, corn, and rice. I first used molecular biology techniques to obtain the genes of interest. Next, I optimized a protocol to produce the proteins of interest in sufficient quantities to study. With the proteins in hand, I then focused my efforts on characterizing their enzymatic activities. I found that the proteins from the different plants possess varying activities. Each protein from the different plants possesses properties that make them more or less interesting for bioengineering and industrial purposes. Starch catabolism requires multiple enzymes to break it down, but my data demonstrate that we can utilize these proteins from a wide array of agriculturally relevant plants and that the proteins have varying enzymatic activities. This allows our lab to move forward towards characterizing the remaining enzymes crucial to starch breakdown and to build a toolkit of different proteins that work under different conditions so that we can meet the needs of industrial starch processing.
In Vitro Starch Catabolism, a Novel, Environmentally Safe Means of Starch Processing.
Starch is a key component in many aspects of daily life, including nutrition, biofuel production, and industrial processing: 50-80% of daily caloric intake comes from starch; >20% of corn starch produced in the U.S. is converted to ethanol; and starch is a cheap and renewable industrial feedstock for producing paper, textiles, adhesives, plastics, and pharmaceuticals. However, starch is difficult to manipulate during industrial processing because it is insoluble in water. Current means of starch processing involves harsh chemicals and present environmental concerns. Starch-based feedstocks are generated using physical, chemical and enzymatic methods. Physical methods include cyclic heating/cooling between 50°C and >100°C. The addition of acids and bases to this process breaks down starch and converts starch to a structure that is more amenable to further processing. Lastly, an enzyme called amylase is utilized to break starch down into simple sugars (i.e. table sugar). Plants synthesize starch every 24 hours during daylight as a means to store energy captured from the sun. Plants then break down starch at night and utilize this stored energy cache. Clearly, plants do not use harsh chemicals or extreme temperatures to break down starch. Instead, they utilize a cyclic system of three classes of enzymes to break down starch: kinases, amylases, and phosphatases. Our lab is exploring how these enzymes break down starch, defining their properties, and optimizing how these enzymes work. To date, most of the work on the proteins from this system has been done using a standard laboratory model organism that is not agriculturally relevant. Therefore, I chose to study these proteins from agriculturally relevant organisms: potatoes, corn, and rice. I first used molecular biology techniques to obtain the genes of interest. Next, I optimized a protocol to produce the proteins of interest in sufficient quantities to study. With the proteins in hand, I then focused my efforts on characterizing their enzymatic activities. I found that the proteins from the different plants possess varying activities. Each protein from the different plants possesses properties that make them more or less interesting for bioengineering and industrial purposes. Starch catabolism requires multiple enzymes to break it down, but my data demonstrate that we can utilize these proteins from a wide array of agriculturally relevant plants and that the proteins have varying enzymatic activities. This allows our lab to move forward towards characterizing the remaining enzymes crucial to starch breakdown and to build a toolkit of different proteins that work under different conditions so that we can meet the needs of industrial starch processing.