1. Metabolism of Bacteria By Ms.Patchanee Yasurin 471-9893 Faculty of Biotechnology Assumption Univerity

2. Why do we must know the metabolism of bacteria ? Because we want to know how to inhibit or stop bacteria growth and want to control their metabolism to prolong shelf-life of food products.

3. What is Metabolism? The Greek metabole, meaning change It is the totality of an organism's chemical processes to maintain life. - Catabolism - Anabolism

4. What are nutrients that bacteria want? C Sugar, Lipid Energy, Biosynthesis N Protein Biosynthesis O Air Energy

5. Biochemical Components of Cells Water: 80 % of wet weight Dry weight Protein 40-70 % Nucleic acid 13-34% Lipid 10-15 % Also monomers, intermediates and inorganic ions

6. Microorganisms require about ten elements in large quantities, because they are used to construct carbohydrates, lipids, proteins, and nucleic acids. Several other elements are needed in very small amounts and are parts of enzymes and cofactors. Concepts: Nutrient requirements

7. Macronutrients Cells make proteins, nucleic acids and lipids Macronutrients macromolecules, metabolism C, H, O, N, S, P, K, Mg, Fe Sources Organic compounds Inorganic salts

8. macronutrients: required in large amounts

9. Micronutrients and growth factors Micronutrients: Metals and metalloids Elements needed in trace quantities Generally not necessary to add to medium Deficiencies can arise when medium constituents are very pure Growth factors: organic requirements Vitamins, amino acids, purines, pyrimidines, acetate

10. micronutrients: required in lesser, sometimes trace amounts not every element is required by all cells

12. growth factors: organic compounds required in small amounts not every growth factor is required by all cells

13. A. Basic Concepts Definitions Metabolism: The processes of catabolism and anabolism Catabolism: The processes by which a living organism obtains its energy and raw materials from nutrients Anabolism: The processes by which energy and raw materials are used to build macromolecules and cellular structures (biosynthesis)

15. Overview of cell metabolism

16. Breakdown Proteins to Amino Acids, Starch to Glucose Synthesis Amino Acids to Proteins, Glucose to Starch

17. Bacterial Metabolism ☺ Exoenzymes: Bacteria cannot transport large polymers into the cell. They must break them down into basic subunits for transport into the cell. Bacteria therefore elaborate extracellular enzymes for the degradation of carbohydrates to sugars (carbohydrases), proteins to amino acids (proteases), and lipids to fatty acids (Lipases).

19. – After Sugars are made or obtained, they are the energy source of life. – Breakdown of sugar(catabolism) different ways: Aerobic respiration Anaerobic respiration Fermentation Energy Generating Patterns

20. Aerobic respiration Glucose is a hexose, monosaccharide, C 6 H 12 O 6 It is systematically broken down through three related “pathways” to Carbon dioxide (CO 2 ) and Water (H 2 O) – Process: 1. Glycolysis (in cytoplasm) 2. Kreb Cycle (in mitochondria) 3. Electron transport chain

21. Glycolysis: Several glycolytic pathways The most common one: glucose-----> pyruvic acid + 2 NADH + 2ATP

22. Glycolysis

23. Glycolytic Pathways 4 major glycolytic pathways found in different bacteria: Embden-Meyerhoff-Parnas pathway “Classic” glycolysis Found in almost all organisms Hexose monophosphate pathway Also found in most organisms Responsible for synthesis of pentose sugars used in nucleotide synthesis Entner-Doudoroff pathway Found in Pseudomonas and related genera Phosphoketolase pathway Found in Bifidobacterium and Leuconostoc

24. Carbohydrate Metabolism 1. Embden–Meyerhof–Parnas (EMP) pathway, glycolysis

26. cyclic “pathway” Pyruvic acid is first acted on by an NZ and a coenzyme (COA). The end product is Acetyl-Coa and a CO 2 molecule. Remember this occurs twice for each glucose molecule. (One glucose is split into two pyruvic acid molecules.)

27. TCA Cycle (Krebs)

28. Return to Krebs and show how it works with electron transport chain. Note how glycolysis and Krebs are working together. Note that each produces reduced carriers that need to be processed.

29. Carbohydrates, fats, and proteins can all be catabolized through the same pathways. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 9.19

31. Lipids are catabolized to Glyerol and Fatty acids Glycerol easily enters glycolysis and Krebs just like pyruvate Fatty acids are chopped into 2 or 3 acid fragments that are broken downt to carbondioxide Even nucleic acids – OH SO MUCH MORE!!! Take biochem.

32. Lipid Metabolism Lipids are essential to the structure and function of membranes Lipids also function as energy reserves, which can be mobilized as sources of carbon 90% of this lipid is “triacyglycerol” triacyglycerol lipase glycerol + 3 fatty acids The major fatty acid metabolism is “β-oxidation”

33. Lipid Metabolism β-oxidation of fatty acid

34. Lipid Metabolism Glycerol Metabolism

35. Other fuels Proteins: digested to amino acids Amino acids are : ‘deaminated’ : amino group removed, the reulting ‘acid’ can be further metabolized, more ATP decarboxylated: carboxyl group removed, the end products then enter glycolysis or Krebs to make ATP

36. Nitrogen Metabolism Nitrogen is an essential element of biological molecules, such as amino acids, nucleotides, proteins, and DNA Bacteria vary widely in their ability to utilize various sources of nitrogen for synthesis of proteins

37. General view of nitrogen metabolism

38. Amino acid degradation

39. Pathways Involved in Nitrogen Utilization 1. Protein Digestion – by proteinase and peptidase 2. Oxidative Deamination

40. 3. Reductive Deamination 4. Decarboxylation

41. 5. Transamination Reactions

42. Anaerobic respiration – Final electron acceptor : never be O2  Sulfate reducer: final electron acceptor is sodium sulfate (Na2 SO4)  Methane reducer: final electron acceptor is CO2  Nitrate reducer : final electroon acceptor is sodium nitrate (NaNO3) O2/H2O coupling is the most oxidizing, more energy in aerobic respiration. Therefore, anaerobic is less energy efficient.

43. Chemoautotroph: Nitrifying bacteria 2 NH 4 + + 3 O 2 2 NO 2 - + 2 H 2 O + 4 H + + 132 Kcal BacteriaElectron donor Electron acceptor Products Alcaligens and Pseudomonas sp. H2H2 O2O2 H2OH2O Nitrobacter NO 2 - O2O2 NO 3 -, H 2 O Nitrosomonas NH 4 + O2O2 NO 2 -, H 2 O Desulfovibrio H2H2 SO 4 2- H 2 O. H 2 S Thiobacillus denitrificans S 0. H 2 SNO 3 - SO 4 2-, N 2 Thiobacillus ferrooxidans F e 2+ O2O2 F e 3+, H 2 O

44. C.Fermentation Features of fermentation pathways Pyruvic acid is reduced to form reduced organic acids or alcohols. The final electron acceptor is a reduced derivative of pyruvic acid NADH is oxidized to form NAD: Essential for continued operation of the glycolytic pathways. O 2 is not required. No additional ATP are made. Gasses (CO 2 and/or H 2 ) may be released

45. Fermentation  Glycosis: Glucose ----->2 Pyruvate + 2ATP + 2NADH  Fermentation pathways a. Homolactic acid F. P.A -----> Lactic Acid eg. Streptococci, Lactobacilli b.Alcoholic F. P.A -----> Ethyl alcohol eg. yeast

46. Some organisms (facultative anaerobes), including yeast and many bacteria, can survive using either fermentation or respiration. For facultative anaerobes, pyruvate is a fork in the metabolic road that leads to two alternative routes. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 9.18

56. Re-Dox Reactions

57. Central Metabolism

58. Glycolysis

59. Fermentation Products

60. Nutrition Table 27.1

61. Alternative energy generating patterns (3)

62. Alternative energy generating patterns (4)

63. Energy/carbon classes of organisms

65. Fig. 5-12

66. Overview of Metabolism

72. Electron Transport Chain

73. Electron Flow and Energy Trapping

75. Microbiology chapters 7 - 8 part 2 Glycolysis: Anaerobic, no oxygen required, linear NZ pathway Begins with ______ End products _________ How much ATP? _______ How many carrier molecules? ____ Name the carrier molecule. ____ Where in the cell? _______ What happens after if the organism Is an aerobe? _____ Facultative? ______ Strict anaerobe? ______ Aerobe deprived of oxygen? ____

76. ATP – Adenosine triphosphate, universal cellular energy Cyclically made and energy is stored and then broken down and the energy is released

77. ATP – Adenosine triphosphate, universal cellular energy Cyclically made and energy is stored and then broken down and the energy is released

79. Microbiology chapters 7 - 8 part 2 Note: ATP is a ribonucleotide, it has ribose, a nitogenous base (adenine), and phosphate. The high energy bond of the terminal of the three phosphates is the one cyclically broken and regenerated. Sugars like glucose can be broken down in a catabolic pathway controlled by many cellular enzymes. Some of the energy released by the breaking of covalent bonds is harvested and stored in the “energy” bonds of ATP. Most any biomolecule can be used for energy; we will focus on the “catabolism” of glucose (a monosaccharide) and later show how the others are involved (lipids, AA, etc)

80. Microbiology chapters 7 - 8 part 2 Note: ATP is a ribonucleotide, it has ribose, a nitogenous base (adenine), and phosphate. The high energy bond of the terminal of the three phosphates is the one cyclically broken and regenerated. Sugars like glucose can be broken down in a catabolic pathway controlled by many cellular enzymes. Some of the energy released by the breaking of covalent bonds is harvested and stored in the “energy” bonds of ATP. Most any biomolecule can be used for energy; we will focus on the “catabolism” of glucose (a monosaccharide) and later show how the others are involved (lipids, AA, etc)

81. Microbiology chapters 7 - 8 part 2 This is a cyclic “pathway” Pyruvic acid is first acted on by an NZ and a coenzyme (COA). The end product is Acetyl-Coa and a CO 2 molecule. Remember this occurs twice for each glucose molecule. (One glucose is split into two pyruvic acid molecules.)

82. Krebs cycle (TCA, Citric acid cycle) Aerobic stage, Occurs in the fluid of the Matrix

83. This is a cyclic “pathway” Pyruvic acid is first acted on by an NZ and a coenzyme (COA). The end product is Acetyl-Coa and a CO 2 molecule. Remember this occurs twice for each glucose molecule. (One glucose is split into two pyruvic acid molecules.)

84. Return to Krebs and show how it works with electron transport chain. Note how glycolysis and Krebs are working together. Note that each produces reduced carriers that need to be processed.

85. Microbiology chapters 7 - 8 part 2 The electrons are passed down the chain and end up being added to oxygen. The Hydrogen ion (H+) is pumped out (proton pump) and flows back in at special sites to be added to the Oxygen and electron to form Water. Energy is conserved (harvested; stored) in the bonds of ATP

86. Theory of Chemiosmosis: Proton pump, increased H+ ion concentration, flow through ATP synthase related channel, energy is harvested in high energy bonds of ATP. Enough to generate 34 more ATP.

87. Carbohydrate Metabolism 2. Entner–Doudoroff (ED) pathway

88. Carbohydrate Metabolism 3. Pentose phosphate (PP) pathway

89. Formation of intermediates of the Embden – Meyerhof – Parnas (EMP) and Entner – Doudoroff (ED) pathway from carbohydrates other than glucose

90. Table 1: Distribution of Embden–Meyerhof–Parnas (EMP), Entner–Doudoroff (ED), and pentose phosphate (PP) pathway in bacteria OrganismEMPEDPP Pseudomonas aeruginosa-+i- Enterococcus faecalis++i+ (Streptococcus) Salmonella typhimurium++i+ Bacillus subtilis+-- Escherichia coli++i+ Yersinia pseudotuberculosis++i- Remark: + = Present; – = not present. i = inducible