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Dr. Ho’s childhood was marked by numerous illnesses, which made her feel inferior to other children of the same age. She felt herself to be a “worthless” child and a burden to her family. This is probably what seeded her strong desire to accomplish something worthwhile in her life and contribute to society if given the chance. After Dr. Ho completed her Ph.D. at Purdue University, she stayed at Purdue for personal reasons. Although she did not vigorously pursue a high-ranking academic position, she always thrived on solving important problems in science and technology. For example, two years after she received her Ph.D. from Purdue, she began to intensely study the development of a new method for fragmenting the structure of DNA – facilitating the analysis of its sequence. Back then DNA was still a “black hole” in molecular biology, with no suitable means to delineate its intricate structure. Her very first proposal for that project (the very first formal proposal she ever submitted) received great reviews from the three agencies the proposal was submitted to – NIH, NSF, and the National Cancer Institute. They all awarded her grants. From that time on, she supported herself as well as the scientists working with her at Purdue University. As a scientist, Dr. Ho’s greatest strength has been her ability to critique her own work and appreciate other scientists’ talent and innovation. After several years of hard work, the method that she was developing for determining DNA structure was proceeding well. However, additional restriction enzymes were discovered by then. She foresaw that restriction enzymes were far superior for tackling the DNA structure. As such, she gave up her own pursuit and vigorously studied these novel restriction enzyme-based recombinant DNA techniques. Within a year or so, she became a specialist in recombinant DNA technology at Purdue. When Purdue’s Laboratory of Renewable Resources Engineering (LORRE) needed such an individual to help them shape their strategy for developing a recombinant microorganism to ferment xylose from biomass, she was recommended to Dr. George Tsao, the Director of LORRE. Once Dr. Tsao contacted her, she was intrigued by the project because it was an ideal case where the application of recombinant DNA technology could make a real difference. Furthermore, if successful, she believed that such engineered yeast could help to solve the world’s energy and economic problems in the future. She decided to join LORRE to lead the study. In the early 1980s, there were about ten groups independently pursuing the task of genetically engineering the Saccharomyces yeast to ferment xylose and more than half of the groups were in the US. Both the USDA (The United States Department of Agriculture) and the DOE (the Department of Energy) National Laboratories had at least one group pursuing this goal as well. Not only was her group the smallest, but Dr. Ho also had to obtain most of her own funding – through grant applications to the Federal Government Agencies – to support her group’s research. As detailed in the Background section of this website, Dr. Ho’s Group at Purdue was the only one that succeeded in the development of the world’s first genetically engineered yeast that could effectively ferment xylose and co-ferment both glucose and xylose to ethanol. Dr. Ho received the prestigious R&D 100 Award as well as the Discover Magazine Award for the development of the yeast. Many of her industrial colleagues also had words of praise for her accomplishments. Dr Ho was able to design and develop this ideal yeast for cellulosic ethanol production not only because she is a dedicated and serious scientist, but more so because she is a problem-solver and a person with vision. When she decided to participate in the genetic modification of the yeast, she had never done any formal research on yeast and knew little about yeast scientifically. After studying the problems that restricted yeast from fermenting xylose and the mechanisms that allowed yeast to effectively convert sugars, including xylose, to ethanol, she designed a detailed plan to make yeast effectively convert not only xylose to ethanol, but xylose together with glucose and other sugars present in cellulosic biomass to ethanol. The latter is important because there is a common genetic mechanism in most microorganisms that prevents them from using other sugars if glucose is present in their surroundings. In her engineered yeast, xylose acts as if it were glucose. Dr. Ho designed her yeast using basic scientific principles, logic, and a fair bit of imagination. Each step and approach was revisited countless times. However, her hard work paid off, and eventually culminated in the development of her successful technology. Since 1993 to the present, her group has continued to improve the Saccharomyces yeast to more cost effectively produce cellulosic ethanol on an industrial scale.
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