Biomass Fundamentals Modules 6 -11 : Carbohydrates: a major building block for biomass

1. Biomass FundamentalsModules 6-11: Carbohydrates: a major building block for biomass A capstone course for BioSUCCEED: BioproductsSustainability: a University Cooperative Center of Excellence in EDucation The USDA Higher Education Challenge Grants program gratefully acknowledged for support

2. This course would not be possible without support from: USDA Higher Education Challenge (HEC) Grants Program www.csrees.usda.gov/funding/rfas/hep_challenge.html

3. Emil Fischer: Father of Carbohydrate Chemistry (1852-1919) • Prof. of Organic Chemistry University of Berlin • Known for his monumental work on configuration of sugars • Also worked on aminoacids, proteins, indoles & stereochemistry • As a Grad. student he discovered phenylhydrazine Nobel prize for Chemistry 1902

4. What is a carbohydrate? Quiz M6/11.1 1. • Carbohydrates are polyhydroxylcompounds general formula Cn(H2O)n “Hydrates of Carbon” • All contain hydroxyl groups -OH primary -CH2OH and secondary =CHOH

5. What is a saccharide? HIGHLIGHT: D-Glucose • A carbohydrate possessing the empirical formula, Cm(H2O)n, or hydrates of carbon analogous to inorganic hydrates (e.g., Fe2 (SO4)3*6H2O) • Shown at left is open chain form (Fischer Projection formula) of D-Glucose, isomer in which the hydroxy on C5 is RIGHT D-Glucose is a stereospecific form of glucose having the orientation specified by the Fisher Projection formula shown at left.

6. Abundance Quiz M6/11.2 Carbohydrates are the most abundant living biomaterial (a substance derived from living systems) on the planet They comprise the bulk of plants, while constituting a significant portion of the cellular membrane of animals (yet, lesser than proteins and lipids) They are however, a significant source of stored energy 1.

7. Typical carbohydrates • D-glucose, D-fructose • Sucrose: common table sugar that is a disaccharide synthesized from dehydration of D-glucose & D-fructose • Lactose: common milk sugar that is a disaccharide of D-glucose & D-galactose

8. Based on glyceraldehyde Structure of carbohydrates 1. • Quiz M6/11.1

9. Common carbohydrates ESSAY At this point, describe in a page or less, how XXX contributes to your lifestyle or how you would like it to

10. Common carbohydrate: sucrose • Dimer • Disaccharide • Indispensable to our way of life! • Notice -acetal linkage The linkage between glucose and fructose responsible for the formation of this dimer known as sucrose is known as a glycosidic bond.

11. Nomenclature 1. Quiz M6/11.4 Monosaccharides - characterized in terms of the number of carbons

12. Nomenclature: part II Shown above are two forms of a generic amino acid (where R = carbon-containing groups) that are said to be “enantiomeric.”

13. Nomenclature: part III C1: Anomeric Carbon α : Axial configuration (vertical to the seat of the chair) β : Equatorial configuration (parallel to the seat of the chair)

14. Most Important Chemical Consideration of Sugars Consider the anomeric carbon! The aldehyde on the one position can be nucleophilically attacked by any of the hydroxyls!

15. Hemiacetalization Concept Key to Carbohydrate Ring Structures

16. Nomenclature of Carbohydrates • D, L Defines the configuration at C5 D has the OH at Right in Fischer projection L has the OH at Left in Fischer projection • Gluco defines the configuration of the OH at C2, C4, C5. These OH’s are on same side while the C3-OH is opposite to others • α,β defines the configuration of the OH at C1, the anomeric carbon • Pyran indicates 6 member ring size • Furan indicates 5 member ring size Examples follow

17. In Glucuronic acid C2, C4, C5 OH’s are on same side

18. Alditols • In Mannitol C2, C4, C5 OH’s are not at same side in Fisher Projection

19. 25 25 [a] [a] D D For aged solutions = +52.7o Conformations Anomers Rotations of Fresh Solutions +19o +112o Reason: Mutarotation is the best evidence for the cyclic hemiacetal structure of D-(+)-glucose

20. Monosaccharides,Hemiacetal Formation II C5 OH attacks aldehyde giving a pyranose ring (6 member structure) C4 OH attacks aldehyde giving a furanose ring (5 member structure)

21. Ring closure between C1 and C4 -OH Ring closure between C1 and C5 -OH

22. Hemiacetalization Concept Key to Carbohydrate Ring Structures

23. Oligosaccharides • consist of several monosaccharide residues joined together with glycosidic linkages • di, tri, tetrasaccharides (depending on the number of monosaccharides) • up to 10 - 20 monosaccharides (depending on analytical techniques i.e GC vs LC/MS)

24. Polysaccharides • refer to polymers composed of a large number of monosaccharides linked by glycosidic linkages

25. Cellulose b-D-anhydroglucopyranose units linked by (1,4)-glycosidic bonds

26. Polysaccharides Polysaccharides are polymers composed of many monosaccharide units linked by glycosidic bonds The glycosidic bond can can have either the α or a β-configuration and be joined to any of the hydroxyl groups at C-2, C-3, C-4 or C-6 The chain can either be Linear or Branched • branches can be single monosaccharide units, chains of two or more units, or chains of a variable number of units

27. Polysaccharides Polysaccharides can be divided into two classes • Homopolysaccharides • consist of only one kind of monosaccharide ex cellulose • Heteropolysaccharides • consist of two or more kinds of monosaccharides ex galactoglucomannans

28. Homopolysaccharides Homopolysaccharides can be further divided by the type(s) of glycosidic linkages Homolinkages - either an α or a βconfiguration to a single position (exclusive of any branch linkages) • that is a single kind of monosaccharide linked by one type of bond α-14, β-14, and so on Heterolinkages - a mixture of a- and b-configurations and/or mixture of positions • usually have a definite pattern for the arrangement of the linkages

29. Heteropolysaccharides Heteropolysaccharides can have the same kind of linkage diversity as with homopolysaccharides, but now associated with one or more of the different kinds of monosaccharide units • infinite degree of diversity of structure

30. Polysaccharides Polysaccharides can not only have different sequences of monosaccharide units, but also different sequences of glycosidic linkages and different kinds of branching • a very high degree of diversity for polysaccharides and their structure-function relationships

31. Plant Polysaccharides The conformation of individual monosaccharide residues in a polysaccharide is relatively fixed, however, joined by glycosidic linkages, they can rotate to give different chain conformations. 1,4 glycosidic linkage 1,6 glycosidic linkage

32. Plant Polysaccharides The different kinds of primary structures that result in secondary and tertiary structures give different kinds of properties • water solubility, aggregation and crystallization, viscosity, gelation, etc. Polysaccharides have a variety of functions • Storage of chemical energy in photosynthesis • Inducing Structural Integrity in plant cell walls

33. Starch Starch is composed completely of D-glucose • found in the leaves, stems, roots, seeds etc in higher plants • stores the chemical energy produced by photosynthesis Most starches are composed of two types of polysaccharides - amylose and amylopectin • amylose - a mixture of linear polysaccharides of D-glucose units linked a-(1-4) to each other • between 250-5,000 glucose residues

34. The Components of Starch Amylose

35. Amylopectin • Amylopectin - a mixture of branched polysaccharides of D-glucose units linked a-(1-4), with ~ 5% a-(1-6) branch linkages • between 10,000-100,000 glucose residues

36. Starch Polymer Components Amylose Amylopectin (1 residue in every 20 is 16 linked to branch off)

37. The Components of Starch Amylopectin Amylose Starch tertiary structure (Helix)

38. Building Blocks of Life

39. Hemiacetalization Concept Key to Carbohydrate Ring Structures

40. Fructose is Bane of Our Civilization • Glycoproteins (biomaterial) from food sugars are sticky – adhere to teeth enamel • Streptococcus mutans also adhere to biomaterial • The glucose of the sucrose is polymerized by glucosyl transferase (enzyme of bacteria) to form plaque • Fructose from the above hydrolysis is released • Bacteria needs anaerobic conditions which are partially supprted by plaque to hydrolyze fructose for energy • Ca3(PO4)2 + CH3CH2(OH)COOH  CaHPO4 + Ca+2  loss of enamel

41. Alditols: Reduction Products Reduced aldehyde end-group D-Mannitol

42. Aldaric Acids: Oxidation Products • Above is oxidation product of D-galactose • Galactaric acid • Why is it not labeled as “D- ?”

43. Sorbitol (D-Glucitol) • It is a polyol discovered in the berries of the mountain ash in 1872 commercially produced by the hydrogenation (reduction) of glucose). • It does not lead to tooth decay. WHY? • 60% as sweet as sucrose with 1/3 fewer calories • Good sugar substitute

44. Relative Sweetness

45. Glucose Derivative Spotlight: Glucosamine Nitrogen • Found in mucin, a glycoprotein constituent of saliva • Plays important role in production, maintenance, and repair of cartilage (prevents bone ends from rubbing) • Used in Europe since 1980s to “offset” onset of osteoarthritis • USA is now touting its benefits (perform search – 906K hits)

46. Most Important Chemical Consideration of Sugars Consider the anomeric carbon! The aldehyde on the one position can be nucleophilically attacked by any of the hydroxyls!

47. Important Oligosaccharides • ,-tetrahalose: glucose disaccharide found in the circulatory systems of insects; energy for insect eggs, larvae, and pupae. Found in fungi & yeasts • Raffinose: widely distributed in plants at low concentration – 1:1:1 D-galactose:D-glucose:D-fructose (galactose+sucrose in which it is on C6 of glucose moiety)

48. Starch (Amylose) • High MW polyglucoside that is plant energy • Can be hydrolyzed to specific oligosaccharides • -Amylase (saliva & pancreatic juice) converts it to maltose and glucose • -Amylase (in plants only) converts it to maltose – NOTE: malt from barley is its common source to BREW BEER

49. Starch, Part Deux • Noncrystalline • Partially water soluble • 25% amylose (linear polysaccharide), 75% amylopectin (branched polysaccharide)

50. Starch Polymer Components Amylose Amylopectin (1 residue in every 20 is 16 linked to branch off)