Monday, April 29, 2013
Exhibit Hall
Although fossil fuels are currently the most economical source of energy, alternative energy sources are being explored as replacements for fossil fuels. The energy content of ethanol is only two-thirds that of gasoline, however, butanol has similar energy content compared to gasoline. Bacteria in the genus Clostridium are known for their ability to produce butanol well into the stationary phase of growth and grow in readily available and inexpensive media. Clostridium produce butanol from a variety of five and six carbon sugars, one of which is xylose. The goal of this research was to develop methods to optimize butanol production. To achieve this, two separate but complementary approaches were taken. First, a model was developed and verified to guide the selection of optimal parameters. Second, proteins that are activated at various stages of the fermentation process were identified. Associated genes can be targeted for enhanced protein expression in future research. The mathematical model is based on the known xylose-butanol fermentation pathway and Michaelis-Menten enzyme kinetics. Experiments were conducted using the bacterium Clostridium beijerinckii in bench-top shakers to verify the model and calibrate parameters of the model. Once the model was tested against data collected from experimental runs, it was used to simulate butanol production over a range of conditions to predict optimal parameter values. Since the simulation and empirical results give parameters for maximum butanol production, this interdisciplinary approach shows great promise for the future economical production of biofuels.