This document summarizes macronutrients, micronutrients, and other components needed for microbial growth. It discusses the major elements of carbon, nitrogen, oxygen, hydrogen, sulfur, phosphorus, and potassium. It also addresses micronutrients including trace elements and vitamins. Finally, it compares defined and complex media, noting defined media allows more control and reproducibility while complex media provides necessary growth factors.

1. Dr. N. Banu
Vels University

2.  Mactronutrients: needed in conc. Larger
than 10-4 M.
 Carbon, nitrogen, oxygen, hydrogen,
sulfur, phosporus, Mg 2+ and K+.
 Microbnutrients: needed in conc. Less
than 10-4 M.
 Trace elements: Mo 2+, Zn 2+, Cu 2+, Mn 2+, Ca 2+,
Na 2+,
 Vitamins, hormones and metabolic
precursors.

3.  Carbon: major source of cellular carbon and energy
 Heterotroph
 Autotroph
 Mixotroph
 Chemoautotrophs
 Phototrophs
 Industrial C sources: molasses(surcrose), starch
(glucose, dextrin), corn syrup and sulfite waste liquor.
 Lab. C sources: glucose, sucrose, fructose.
 Chemical subs: methanol, ethanol, methane.
 Aerobic: 50% - biomass; 50% energy.
 Anaerobic: large – biomass; small fraction- energy.

4.  10-14% dry wt.
 Sources: ammonia
 Ammonium salts (NH4cl, NH4NO3,
(NH4)2SO4, Protein, peptides, amino acids.
 N – incorporated into cell mass as proteins
and nucleic acids.
 Atm. Nitrogen: fixed by Azotobacter and
cyanobacteris and forms ammonia.
 Urea- used by some microbe
 Yeast extract and peptone (organic N
source) – expensive than ammonium salts.

5.  Oxygen: present in organic cell
components and cellular water.
 20% dry wt.
 mole. Oxygen – terminal e- acceptor in
aerobic metabolism.
 Gaseous oxygen – media (sparging air or
by surface aeration.

6.  Hydrogen: 8% dry wt.
 Primarily derived from carbohydrates.
 Methanogens uses hydrogen as energy
sources.
 Phosphorus: 3% dry wt.
 Present in nucleic acid.
 cell wall of gram+ bacteria such as
teichoic acid.
 Sources: inorganic phosphate salts-
KH2PO4, K2HPO4.
 Glycerophosphates – organic phosphate.
 Phosphorus – controls cell metabolism
 P-level 1mM –formation of sec. metabolites.

7.  Sulfur: 1% dry wt.
 Present in proteins and coenzymes.
 Sources: sulfate salts (NH4)2SO4
 Sulfur containing amino acids – autotrophs
uses S2+and So as energy sources.
 Potassium:
 Cofactor for some enzymes.
 Required for carbohydrate metabolism.
 Cells take up K+ and Mg2+ excludes Na+
and Ca2+
 Sources: KH2PO4, K2HPO4, and K3PO4.

8.  Magnesium: cofactor for some enzymes.
 Present in cell wall and membrane
 Ribosomes requires Mg2+ ions
 Sources: MgSO4. 7H20; MgCl2.

9.  Essential to microbial nutrition.
 Lack of essential trace elements
increases the lag phase and decreases
specific growth rate and yield.
 1. widely needed trace elements.
 2. trace elements needed under
specific growth.
 3. trace elements rarely required.

10.  Fe: present in ferrodoxin and
cytochrome ;
 Cofactor; plays regulatory role in some
fermentation.
 Zn: cofactor for some enzyme
 Regulates penicillin fermentation.
 Mn: enzyme cofactor
 Regulation of sec. metabolism and
excretion of primary metabolites.

11.  Copper (Cu): present in respiratory chain
components and enzymes.
 Cu deficiency stimulates penicillin and citric
acid production.
 Cobalt (Co): present in corrinoid compounds
such as vit. B12.
 Propionic bacteria and mehtanogens requires
Co.
 Molybdenum (Mo): cofactor of nitrate
reductase and nitrogenase.
 Required for growh on No3 and N2 as sources
of nitrogen.

12.  Calcium (Ca): cofactor for amylase, protease.
 Present in some bacterial spores and cell wall
of plant cell.
 Sodium Na: needed by bacteria
(methanogens).
 Imp. In transport of charged species in
eukaryotic cell.
 Chloride (Cl-): halobacteria and marine
microbe.
 Nickel (Ni): methanogens as cofactor
 Selenium (Se): formate metabolism.

13.  B, Al, Si, Cr, V, Sn, Be, F, Ti, Ga, Ge, Br, Zr, W,
Li and I – req. conc. Is less than 10-6 M.
 Mg2+, Fe3+ and PO43_ precipitate in the
medium.
 chelating agents- used to solubilize the
ions;
 Major ligands – COOH; NH2; mercapto (-SH)
 Chelating agents: citric acid, EDTA,
polyphosphates, histidine, tyrosine and
cysteine.

14.  Stimulate growth and synthesis of metabolites.
 Vitamins, hormones, and aminoacids.
 Vitamins: coenzymes., B1, B2, B6, biotin, B12,
folic acid, lipoic acid, p-aminobenzoic acid
and vit.K.
 10-6 M to 10-12 M.
 Aminoacids supplied externally.
 Fatty acids such as oleic acid and sterols –
small quant.
 Plant and animal – needs hormones.
 Insulin- animal
 Auxin, cytokinins – plant.

15.  Defined media
 Complex media.
 Defined media:
 Specific amt of pure chemicals with known
composition. Eg. Glucose, (NH4)2SO4,
K2HPO4 and MgCl2.
 Adv.:
 Results reproducible
 Control of feremtation
 Recovery and product purification is easier
and cheaper.

16.  Natural compounds, chemical
composition is not exactly known. Eg.
Medium with yeast extact , peptone,
molasses, corn steep liquor.
 Adv.: provided necessary growth factor
 Vitamins, hormones and trace elements.
 Higher yield compared to defined
 Less expensive than defined.