Macronutrients : C,H,N,O,P,S Nutrition Macronutrients : C,H,N,O,P,S

Carbon Required for the synthesis of all organics Sources Carbohydrates Lipids Proteins Nucleic acids  Sources Organic Monosaccharides, disaccharides, polysaccharides, proteins, lipids, nucleic acids, phenols, etc. Inorganic CO2 and CO

Phosphorous Required for the synthesis of: Sources: Nucleic acids Phospholipids ATP Sources: Organic and inorganic The inorganic form is the most used

Nitrogen Required for the synthesis of: Sources: Amino acids Nucleic acids Peptidoglycan Sources: Organic: amino acids Inorganic: NH3, NO3 & N2

Sulfur Required for the synthesis of: Sources: Amino acids (Cysteine/Methionine) Vitamins (thiamine and biotin) Sources: Organic: amino acids Cysteine and methionine Inorganic: S, SO4

Hydrogen and Oxygen Required for the synthesis of all organics! Carbohydrates Lipids Proteins Nucleic acids Sources: Organic: Any organic compound Inorganic: H2 (Methanogens only) H2O (Mainly autotrophs)

Nutritional Classification Carbon source Heterotrophs : Preformed organic molecules Autotrophs: Inorganic molecules CO2 and CO

Nutritional Classification (cont’d) Source of energy Phototrophs: Light Chemotrophs: Oxidation of either organic or inorganic compounds Source of e- Organotrophs: Reduced organic molecules Lithotrophs: Reduced inorganic molecules

Nutritional Types Nomenclature: Source of Carbon-Energy-Electrons Ex. Autotroph photolithotroph Heterotroph photoorganotroph Autotroph chemolithotroph Heterotroph chemoorganotroph

Producing Energy Oxidative-Respiration Fermentation Aerobic Anaerobic O2 used as a final e- acceptor Anaerobic Inorganic final e- acceptor other than O2 is used Fermentation Organic final e- acceptor is used

Microbial Energy Metabolism Glycolytic pathways Respiration Fermentation Chemolithotrophy Photosynthesis

Glycolytic Pathways Glycolysis: Most common glycolytic pathway Partial oxidation of glucose to pyruvate Net production of 2 ATP 2 NAD are reduced to NADH Each of these steps is carried out twice for each glucose molecule

Respiration Features Pyruvate is completely oxidized to CO2 NADH is oxidized to NAD Essential for continued operation of glycolytic pathways Uses an inorganic electron acceptor Aerobic respiration: O2 is the final e- acceptor Anaerobic respiration: An inorganic substance other than O2 is the final e- acceptor Ex. nitrate, nitrite, sulfate Additional ATP are made

Respiration – Electron Transport Chain Aerobic respiration : Final e- acceptor: O2 3 ATP/NADH 2 ATP/FADH Anaerobic respiration: Final e- acceptor other than O2: NO3, NO2, SO4, etc.

Fermentation Features Pyruvate is reduced to organic acids or alcohols Final e- acceptor is organic NADH is oxidized to NAD: Essential for continued operation of glycolytic pathways O2 is not required No additional ATP made Gasses (CO2 and/or H2) may be released

Culture Media

Types of Media Liquid (Broths) Solid media Allows growth in suspension Uniform distribution of nutrients, environmental parameters and others Allows growth of large volumes Solid media Same as liquid media + solidification agent Agar: Polysaccharide derived from an algae

Growth in Broths Non inoculated clear Turbid + sediment Turbid Clear + sediment

Growth on Agar Growth on solid surface Isolated growth Allows isolation of single colonies Allows isolation of pure cultures Easier for counting colonies and observing morphology of colonies. Plates are used to: grow and culture bacteria, fungi, animal tissues, or plant tissues obtain separated pure cultures of bacteria (plate streaking) count colonies from serial dilutions test for growth and reactions on certain materials (such as manitol-salt, or blood agar) test for bacteria viruses (bacteriophages) test for resistance to materials (such as antibiotics) or nutritional needs (this is also used to select for bacteria with certain properties or favor the growth of one type/strain over others) Single colony

Solid Media (Cont’d) Slants Stab Growth on surface and in depth Different availabilities of oxygen Stab Semi-solid medium Long term storage Low availability of oxygen

Nutritional Complexity Nutritional complexity is a function of the biosynthetic capacity The greater the biosynthetic capacity, the lower the nutritional requirements

Complex Media Composed of rich and complex ingredients Ex. Soya protein extracts Milk protein extracts Blood products Tomato juice, etc. Exact chemical composition is unknown Can be selective and/or differential

Defined Media Known chemical composition Can contain up to 80 different ingredients Can be very simple Allows the growth of a restricted number of microorganisms Composition is highly variable according to the microorganism Can be selective and/or differential

Selective Media Contain compounds which inhibit or kills the undesired organisms Ex. Medium containing penicillin only allows the growth of penicillin resistant microorganisms

Differential Media Allows to discriminate different species Often contain pH indicators Allows to discriminate different metabolisms Production of alkali changes medium to red Production of acid changes medium to yellow

Environmental Parameters Oxygen requirements pH Temperature Solute concentration/Water availability

Oxygen Requirements Aerobic: Microaerophilic: Absolute requirement of oxygen for survival Oxygen is used as a final electron acceptor Oxygen is used by bacteria which have an oxidative metabolism or perform aerobic respiration Microaerophilic: Absolute requirement for low oxygen concentrations High concentrations are deadly

Oxygen Requirements (cont’d) Anaerobic/Aerotolerant: Oxygen is tolerated but not required Facultative anaerobes: Facultative oxygen requirement Can choose to use oxygen or not Have an oxygen dependent and an oxygen independent metabolism Strict or obligate anaerobes: Oxygen is not used nor tolerated; cannot survive in the presence of oxygen