Microbial Nutrition
A nutrient is a element or chemical substances that nourishes or
promotes growth and repairs the natural damage of organic life. Organic
and Inorganic compounds are included as nutritional requirements.
Organic nutrients include carbohydrates, fats, proteins and vitamins. Inorganic chemical compounds such as dietary minerals, water and oxygen etc.
Nutritional requirements:
* The biomass of microorganisms can be measured by determining the fresh weight or the dry weight, the fresh weight contains about 80-90 % water and remaining is dry matter.The dry matter is composed of 50% proteins, 10-20% cell wall materials, 10% lipids, 10-20% RNA, 3-4 % DNA.
* Microbial nutrients are further classified as Macro Nutrients and Micro Nutrients depending upon the amount required.
Macro Nutrients ( C, O, H, N, S, P, K, Ca, Mg, Fe) :-
# There are 10 macro nutrients present, because they are required by micro organisms in relatively large
amounts.
# Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur and Phosphorous are components of carbohydrates, lipids,
proteins and nucleic acids. the remaining four elements ( K, Ca, Mg, Fe) exist in the cell as cations.
K+ is requied for the activity by a number of enzymes, including those involved in protein synthesis.
Mg 2+ stabilizes the ribosome, cell membranes and nucleic acidds and activates enzymes.
Ca 2+ Stabilization of cell wall, contributes to the heat resistance of bacterial endospores.
Fe2+ and Fe3+ co-factor for enzymes and electron carrying proteins, part of cytochromes.
Na+ It is the electrolyte balancing the electrical charge and solute concentrations inside the cell cytoplasm.
Micro Nutrients (Co, Cu, Mn, Mo, Cl, Na, B, Ni, Si, Se, W, Va and Zn):-
These are often referred as minor nutrients or trace elements. micro elements are metals playing the role of cells catalysts and many of them play a structural role in various enzymes or co-enzymes. These include Copper, Cobalt, Manganese, Sodium, Boron, Silicon, Nickel, Selenium,Tungsten, Selenium,
Vanadium and zinc.
Cu - It is required by certain enzymes which are involved in respiration.
Co- Component of vitamin-B12
Zn- Plays structural role in RNA and DNA polymerase enzyme.
Mn- Aids many enzymes catalyzing the transfer of phosphate groups.
Ni- Required by hydrogenase enzyme for its activity.
Mo- Required by Nitrogenase enzyme which converts atmospheric nitrogen to ammonia during nitrogen
fixation.
Se &W- Stimulate growth of Methanococcus vannielli on formate.
Va- Occurs in vanadium nitrogenase, bromoperoxidase.
Besides macro and micro nutrients, some micro organisms may have particular requirements that reflect the special nature of their morphology or environment. Diatoms need silicic acid to construct their beautiful cell walls of silica. Bacteria growing in saline lakes and oceans depend on the presence of high concentrations of sodium ion. Microorganisms require a balanced mixture of all the above nutrients for proper growth.
Organic nutrients include carbohydrates, fats, proteins and vitamins. Inorganic chemical compounds such as dietary minerals, water and oxygen etc.
Nutritional requirements:
* The biomass of microorganisms can be measured by determining the fresh weight or the dry weight, the fresh weight contains about 80-90 % water and remaining is dry matter.The dry matter is composed of 50% proteins, 10-20% cell wall materials, 10% lipids, 10-20% RNA, 3-4 % DNA.
* Microbial nutrients are further classified as Macro Nutrients and Micro Nutrients depending upon the amount required.
Macro Nutrients ( C, O, H, N, S, P, K, Ca, Mg, Fe) :-
# There are 10 macro nutrients present, because they are required by micro organisms in relatively large
amounts.
# Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur and Phosphorous are components of carbohydrates, lipids,
proteins and nucleic acids. the remaining four elements ( K, Ca, Mg, Fe) exist in the cell as cations.
K+ is requied for the activity by a number of enzymes, including those involved in protein synthesis.
Mg 2+ stabilizes the ribosome, cell membranes and nucleic acidds and activates enzymes.
Ca 2+ Stabilization of cell wall, contributes to the heat resistance of bacterial endospores.
Fe2+ and Fe3+ co-factor for enzymes and electron carrying proteins, part of cytochromes.
Na+ It is the electrolyte balancing the electrical charge and solute concentrations inside the cell cytoplasm.
Micro Nutrients (Co, Cu, Mn, Mo, Cl, Na, B, Ni, Si, Se, W, Va and Zn):-
These are often referred as minor nutrients or trace elements. micro elements are metals playing the role of cells catalysts and many of them play a structural role in various enzymes or co-enzymes. These include Copper, Cobalt, Manganese, Sodium, Boron, Silicon, Nickel, Selenium,Tungsten, Selenium,
Vanadium and zinc.
Cu - It is required by certain enzymes which are involved in respiration.
Co- Component of vitamin-B12
Zn- Plays structural role in RNA and DNA polymerase enzyme.
Mn- Aids many enzymes catalyzing the transfer of phosphate groups.
Ni- Required by hydrogenase enzyme for its activity.
Mo- Required by Nitrogenase enzyme which converts atmospheric nitrogen to ammonia during nitrogen
fixation.
Se &W- Stimulate growth of Methanococcus vannielli on formate.
Va- Occurs in vanadium nitrogenase, bromoperoxidase.
Besides macro and micro nutrients, some micro organisms may have particular requirements that reflect the special nature of their morphology or environment. Diatoms need silicic acid to construct their beautiful cell walls of silica. Bacteria growing in saline lakes and oceans depend on the presence of high concentrations of sodium ion. Microorganisms require a balanced mixture of all the above nutrients for proper growth.
