Laboratory Experiment to Determine atch Ethanol 实验室实验确定批乙醇.pptVIP

Laboratory Experiment to Determine Batch Ethanol Production by S. cerevisiae Benjamin Reves May 11, 2005 Outline Background Theory Procedure Results Conclusions Recommendations Impact Questions Background Need for Ethanol Ethanol used as raw material and solvent in the chemical, food, and pharmaceutical industries Four million tons of ethanol are produced each year Eighty percent by fermentation Energy Information Administration has predicted annual consumption growth in U.S. of 3.2% each year Saccharomyces cerevisiae Common type of yeast Eucaryotic Reproduces by budding Can grow aerobically or anaerobically Current Methods Batch Reactor Fed-batch Reactor Continuous Reactor Packed Bed Reactor Theory Glycolysis Breakdown of 6-C glucose into two molecules of 3-C pyruvate Fate of pyruvate Aerobic Conditions- TCA cycle Anaerobic Conditions- Converted to ethanol via acetaldehyde Cell Growth Substrates + cells extracellular products + more cells Batch Growth Lag Phase Exponential Growth Phase Deceleration Phase Stationary Phase Death Phase Yield Coefficients Help to quantify growth kinetics YX/S=-?X/?S YP/S= -?P/?S YP/X= ?P/?X Product Formation Growth-associated products Non-growth-associated products Mixed-growth-associated products Temperature Effects Optimal temperatures Product formation affected Diffusion limitations Objectives Objectives Study ethanol production and glucose utilization by Saccharomyces cerevisiae Study effect of temperature on fermentation Construct growth curves Methods Stages of Experimentation Autoclaving Inoculation Growth of Culture Analyzing Samples Autoclaving Sterility is a must! Saturated steam at 121oC used to kill all spores Autoclave Preparing Inoculum Inoculum is typically 5-10% of total working volume Yeast obtained from microbiology department on plates Inoculating needle used to take yeast from plate into 800 mL of YEB Placed on shaker at 30oC Importance of inoculum condition Inoculum Preparation Yeast E