Microbial nutrition
Chapter 11,1 and 3.3
The goal for a bacterial cell is for one to become two
Metabolism is crucial as cells must acquire and synthesize the necessary components for cellular
division
Elements of life
• Organisms are composed of a wide variety of elements called macro-elements or
macronutrients – required in relatively large amounts
• All micro-organisms also require several nutrients in small amounts – micro-elements or trace
elements
General nutrition requirements
• C, O, H, N, S, P, K, Ca, Mg, Fe - consists of 95% of cell mass
• C, H, O, N, S, P – is part of the carbohydrate, lipids, proteins and nucleic acids
• K, Ca, Mg, Fe – are cations involved in various reactions
• Macro-nutrients or macro-elements
, • Potassium: responsible for enzyme activity
• Calcium: contributes to heat resistance in endospores
• Magnesium: cofactor for many enzymes
• Iron- part of cytochrome
• Micro-nutrients or trace elements
• Mn, Zn, Co, Ni, Mo, Cu
- Needed in low concentrations
• Typically form part of enzymes and are involved in enzyme reactions
Requirements of N, P, and S
• Grow and reproduce – micro-organism must be able to incorporate large quantities of N, P, S
• N – necessary for many cell components – amino-acids, purines, pyrimidines, etc.
- Acquire from same source as C-source
- Some directly from ammonia
- Atmospheric N! : nitrogen fixation
• P present in nucleic acids, phospholipids, ATP, etc.
• Inorganic phosphate source
- Low P-levels in aquatic environments can limit growth
• S present in aa, biotin, etc.
- Most microbes use sulphates as S-source
Requirements of C, H and O
• All organisms need C, H, O and a source of electrons
• C needed to synthesize the organic molecules from which organisms are built
• H and O also important elements found in organism molecules
• Electrons needed as:
- Electron movement supplies energy
- Reduce molecules during biosynthesis
, • Requirements for C, H, O satisfied together as molecules serving as C sources provide H and O as
well
Simple model of metabolism
Requirements of C, H and O
• Autotroph
- Use CO! as their source of carbon
- Can use light as an energy source
- Mostly photosynthesizing organisms
- Although carbon dioxide is plentiful it does not supply hydrogen or energy to the cell
- Most bacteria can fix CO!
- The fixation of CO! is a very energy demanding process
- Most bacteria will use other complex molecules as source of carbon dioxide
• Heterotroph
- Use reduced previously formed organic compounds as their carbon and energy sources
- Reduced molecules usually from other organisms
- Carbon sources usually also energy sources
- Flexibility with respect to carbon sources
• Microbes are flexible with respect to carbon sources
• All naturally occurring organic molecules can be used by some microbe
• Actinomycetes can degrade amyl alcohol, paraVin and rubber
Chapter 11,1 and 3.3
The goal for a bacterial cell is for one to become two
Metabolism is crucial as cells must acquire and synthesize the necessary components for cellular
division
Elements of life
• Organisms are composed of a wide variety of elements called macro-elements or
macronutrients – required in relatively large amounts
• All micro-organisms also require several nutrients in small amounts – micro-elements or trace
elements
General nutrition requirements
• C, O, H, N, S, P, K, Ca, Mg, Fe - consists of 95% of cell mass
• C, H, O, N, S, P – is part of the carbohydrate, lipids, proteins and nucleic acids
• K, Ca, Mg, Fe – are cations involved in various reactions
• Macro-nutrients or macro-elements
, • Potassium: responsible for enzyme activity
• Calcium: contributes to heat resistance in endospores
• Magnesium: cofactor for many enzymes
• Iron- part of cytochrome
• Micro-nutrients or trace elements
• Mn, Zn, Co, Ni, Mo, Cu
- Needed in low concentrations
• Typically form part of enzymes and are involved in enzyme reactions
Requirements of N, P, and S
• Grow and reproduce – micro-organism must be able to incorporate large quantities of N, P, S
• N – necessary for many cell components – amino-acids, purines, pyrimidines, etc.
- Acquire from same source as C-source
- Some directly from ammonia
- Atmospheric N! : nitrogen fixation
• P present in nucleic acids, phospholipids, ATP, etc.
• Inorganic phosphate source
- Low P-levels in aquatic environments can limit growth
• S present in aa, biotin, etc.
- Most microbes use sulphates as S-source
Requirements of C, H and O
• All organisms need C, H, O and a source of electrons
• C needed to synthesize the organic molecules from which organisms are built
• H and O also important elements found in organism molecules
• Electrons needed as:
- Electron movement supplies energy
- Reduce molecules during biosynthesis
, • Requirements for C, H, O satisfied together as molecules serving as C sources provide H and O as
well
Simple model of metabolism
Requirements of C, H and O
• Autotroph
- Use CO! as their source of carbon
- Can use light as an energy source
- Mostly photosynthesizing organisms
- Although carbon dioxide is plentiful it does not supply hydrogen or energy to the cell
- Most bacteria can fix CO!
- The fixation of CO! is a very energy demanding process
- Most bacteria will use other complex molecules as source of carbon dioxide
• Heterotroph
- Use reduced previously formed organic compounds as their carbon and energy sources
- Reduced molecules usually from other organisms
- Carbon sources usually also energy sources
- Flexibility with respect to carbon sources
• Microbes are flexible with respect to carbon sources
• All naturally occurring organic molecules can be used by some microbe
• Actinomycetes can degrade amyl alcohol, paraVin and rubber
