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  1. 1. Glucose Isomerization February 28, 2006 Kate Cannady Chris Miller Matt Mobily Jennifer Pratt Separations & Reaction Engineering Lab
  2. 2. <ul><li>C 6 H 12 O 6 </li></ul><ul><li>aka Dextrose (rotates polarized light to right) </li></ul><ul><li>Monosaccharide (simple sugar) </li></ul><ul><li>One of most important carbohydrates </li></ul><ul><ul><li>Glucose Energy </li></ul></ul><ul><ul><li>Critical in protein production and lipid metabolism </li></ul></ul><ul><ul><li>Cellular use as source of energy and metabolic intermediate </li></ul></ul><ul><ul><li>One of the main products of photosynthesis </li></ul></ul>Glucose - What To Know Chain Structure - D-Glucose 6 Membered Ring - D-Glucose
  3. 3. Fructose - What To Know <ul><li>Same formula as glucose, but different structure </li></ul><ul><li>aka Levulose (rotates polarized light to left) </li></ul><ul><li>Sweeter than glucose due to stereomerism structure </li></ul><ul><li>Along with glucose & galactose, one of the most important blood sugars </li></ul><ul><ul><li>Studies have shown that substituting fructose for sucrose in diabetics improves glycemic contol </li></ul></ul>Chain Structure - D-Fructose 5 Membered Ring - D-Fructose
  4. 4. What Is Glucose Isomerase? <ul><li>An enzyme that aides in conversion of glucose to fructose </li></ul><ul><li>~42% conversion to fructose </li></ul><ul><li>More expensive, but is reused until most of it’s activity is lost as opposed to other enzymes which can be used only once </li></ul><ul><li>Typically, the enzyme is packed into column where glucose mixture is then passed over it </li></ul><ul><li>Gensweet IGI-HF by Genencor International </li></ul><ul><ul><li>Immobilized – granular vs. in solution </li></ul></ul><ul><ul><li>Produced from genetically modified strain of Streptomyces Rubiginosus </li></ul></ul><ul><ul><li>Gensweet IGI-HF – conversion of 44% fructose based on standard conditions of 40% w/w glucose, temperature of 60˚C and pH of ~7.5 </li></ul></ul>Specific Enzyme Used:
  5. 5. Industrial Relevance <ul><li>Fructose is much sweeter than glucose or sucrose </li></ul><ul><ul><li>Glucose = 75% sweetness of sucrose </li></ul></ul><ul><ul><li>Fructose = 2 x sweetness of sucrose </li></ul></ul><ul><li>Cheaper to use fructose because less is required to achieve the same sweetness </li></ul><ul><li>$4.5 Billion per year sold in U.S. </li></ul><ul><li>Production of high fructose corn syrup (HFCS) from cornstarch </li></ul><ul><ul><li>Isomerization of glucose to fructose is last step in production </li></ul></ul><ul><ul><li>Used at ambient temps & pH’s – better conditions than chemical production </li></ul></ul>
  6. 6. Design Challenge <ul><li>Build on last semesters lab concerning conversion by glucose isomerase </li></ul><ul><ul><li>Recall: </li></ul></ul><ul><ul><ul><li>Samples of pure glucose & fructose solutions were placed in SR-6 Polarimeter and optical rotations observed. ( ~63(+) for glucose, 90(-) for fructose ) </li></ul></ul></ul><ul><ul><ul><li>Glucose solution w/ hydrated enzyme placed in water bath for ~48 hours to observe conversion </li></ul></ul></ul><ul><li>Using a PBR (Packed Bed Reactor) and enzyme provided by Genencor, pump in glucose solution at various feed rates and observe conversion to fructose </li></ul><ul><li>Use data and calculated results to scale-up for an industrial PFR for isomerization from glucose to fructose </li></ul>Ultimate Goals: 1. Determine and understand which parameters involved in the operation affect the conversion of glucose to fructose 2. How are they inter-related?
  7. 7. Theory <ul><li>Enzymes </li></ul><ul><ul><li>High MW protein or protein-like substance </li></ul></ul><ul><ul><li>Acts on a substrate to chemically transform it at a greatly accelerated rate (~10 3 to 10 17 times faster) – make life possible </li></ul></ul><ul><ul><li>Lowers E a </li></ul></ul><ul><ul><li>Not consumed during reaction, nor do they affect reaction equilibrium </li></ul></ul>Proceeds as: S = substrate E = enzyme ES = active intermediate P = product
  8. 8. Michaelis-Menten…in a nutshell Solve for intermediates using SSA Vmax = maximum rate appearance of fructose [G] = concentration of glucose KM = derived constant W = weight of enzyme ρ E = density of the enzyme F GO = flow rate of feed into system Theory Could determine V max & K M from Lineweaver-Burk Plot; intercept = 1/V max , slope = K M /V max + Design equation for PBR Combine equations and integrate to get ‘w’ as a function of K m , V max , F A0 and x Using equation derived for ‘w’, set up Excel spreadsheet to find K M and V max for corresponding F G and x
  9. 9. Experimental Setup <ul><li>45% w/w glucose solution prepared </li></ul><ul><ul><li>added Mg(HSO 3 ) 2 for necessary ion concentration </li></ul></ul><ul><ul><li>pH adjusted to ~7.8 </li></ul></ul><ul><li>Solution pumped through at various flow rates </li></ul><ul><ul><li>Refractometer used to ensure previous solution fully exited from reactor </li></ul></ul><ul><ul><li>Optical rotations observed in SR-6 Polarimeter for solutions to determine conversion </li></ul></ul><ul><ul><ul><li>repeated until steady state achieved </li></ul></ul></ul><ul><ul><li>Adjust flow rate and repeat </li></ul></ul>pump PBR Initial glucose solution glucose/fructose product solution
  10. 10. Preliminary Results
  11. 11. Conclusions & To Do... <ul><li>To Do: </li></ul><ul><ul><li>Integrate & solve equations to obtain ‘w’ in terms of K m , V max , F A0 and x </li></ul></ul><ul><ul><li>Set up Excel to find K m and V max </li></ul></ul><ul><ul><li>Determine relationships between them </li></ul></ul><ul><ul><li>Use data to determine scale-up reactor for conversion of glucose to fructose </li></ul></ul><ul><li>Conclusions: </li></ul><ul><ul><li>Data shows expected correlation between flow rate and conversion </li></ul></ul><ul><ul><ul><li>Faster flow rates = less conversion </li></ul></ul></ul><ul><ul><ul><li>Slower flow rates = higher conversion </li></ul></ul></ul>
  12. 12. References <ul><li>Cannady, K. Photos. </li></ul><ul><li>DePaula, J., & Atkins, P. (2001). Physical Chemistry . 7 th Edition. W.H.Freeman </li></ul><ul><li>Fogler, H.S. (2006). Elements of Chemical Reaction Engineering . 4 th Edition. Prentice Hall. </li></ul><ul><li>Perry, R.H. and D. W. Green. (1997) Perry’s Chemical Engineers’ Handbook . 7th Edition. New York: McGraw-Hill. </li></ul>
  13. 13. Questions?