NUTRITION AND

CULTIVATION OFMICROORGANISM

Why need Nutrients?

Obtain Energy

Grow

Metabolic activity

Replicate

New cellular component

Growth of Microbes

Manipulation of growth is important for infection control growth of industrial and biotech

organisms

To understand Nutritional

requirement of microorganism it

is necessary to understand the

chemical composition of the

microbial cell

Major elemental composition of Microbial cell

Ele % DCW

Chemical form used by the microbe

Physiological functions

C 50 Organic compounds, CO, CO2 major constituents of cell materialproteins, nucleic acids, lipids,carbohydrates and others

O 20 Organic compounds, H2O ,O2, CO2

N 14 Organic compounds, NH4+, NO3-, N2

H 8 Organic compounds, H2O, H2

P 3 HPO42- nucleic acids, phospholipids, teichoicacid, coenzymes

S 1 organic sulfur compounds, SO42-,HS-, S0, S2O32-

proteins, coenzymes

k 1 K+ major inorganic cation, compatiblesolute, enzyme cofactor

Na 1 Na+ transport, energy transduction

Ca 0.5 Ca2+ enzyme cofactor, bound to cell wall

Mg 0.5 Mg2+ enzyme cofactor, bound to cell wall,membrane & phosphate esters

Cl 0.5 Cl- major inorganic anion

Fe 0.2 Fe2+, Fe3+ cytochromes, ferredoxin, cofactor

Requirement for C, H & O Requirement of C,H & O satisfied together Carbon needed as backbone of all organic molecule Carbon source also contribute to oxygen & hydrogen Organic compound mainly serve C, H & O Organic compound electron electron

acceptor

Organic compound

Energy

electron acceptor

One important carbon source that does not supply hydrogen

or energy is carbon dioxide (CO2).

(reduce)

(oxidize)

(oxidize)

(reduce)

Nitrogen Nitrogen -primarily to form the amino group

of the amino acids of proteins

Nitrogen sources commonly used by microbes include organic nitrogenous compounds such as amino acids, and inorganic forms such as ammonium and nitrate

Gaseous N2 can serve as a nitrogen source for a limited number of nitrogen-fixing prokaryotes.

Some chemolithotrophs can use ammonium as their energy source (electron donor)

while nitrate can be used as an electron acceptor by denitrifiers

Sulfur

Sulfate is the most commonly used sulfur source,

while other sulfur sources used include organic sulfur compounds, sulfide, elemental sulfur and thiosulfate.

Sulfide and sulfur can serve as electron donors in certain chemolithotrophs .

sulfate and elemental sulfur are used as electron acceptors and reduced to sulfide by sulfidogens.

Micronutrient required by Microbial cellElement Chemical form

used by the microbe

Physiological functions

Mn Mn2+ superoxide dismutase, photosystem II

Co Co2+ coenzyme B12

Ni Ni+ hydrogenase, urease

Cu Cu2+ cytochrome oxidase, oxygenase

Zn Zn2+ alcohol dehydrogenase, aldolase, alkaline phosphatase, RNA and DNA polymerase, arsenate reductase

Se SeO32- formate dehydrogenase, glycine reductase

Mo MoO42- nitrogenase, nitrate reductase, formate dehydrogenase, arsenate reductase

W (tungste

n)

WO42- formate dehydrogenase, aldehyde oxidoreductase

Metals required for yeast cell growth & Metabolic function Metal ion

conc,. Main cellular functions

Macroelements

K 2-4 mM

Osmoregulation, enzyme activity

mg 2-4 mM

Enzyme activity, cell division

Microelements

Mn 2–4 µM

Enzyme cofactor

Ca < µM Second messenger, yeast flocculation

Cu 1.5 µM Redox pigments

Fe 1–3 µM

Haem-proteins, cytochromes

Zn 4–8 µM

Enzyme activity, protein structure

Ni 10 µM Urease activity

Mo 1.5 µM Nitrate metabolism, vitamin B12

Co 0.1 µM Cobalamin, coenzymes

S. Cerevisiae growth stimulation but depend on yeast species/strain & precise growth condition

Sodium is the other main monovalent cation

yeast cells may sometimes contain quite high levels of sodium,

fermentation media are also often high in sodium,

sodium metal appears to be non-essential for yeast

under normal growth conditions, S. cerevisiae actively excretes sodium (via a sodium-proton antiporter) to maintain intracellular sodium at very low, sub-toxic levels

Calcium requirements for cell division and growth are also very low – considered trace metal

Calcium binds to yeast cell walls and plays a key role in flocculation

Calcium also antagonises uptake of magnesium and can block essential magnesium dependent metabolic processes

zinc is particularly important with regard to its role as activator of the terminal alcohologenic Zn-metalloenzyme ethanol dehydrogenase.

Media deficient in zinc may lead to slow or incomplete fermentations

ROLES FOR MAGNESIUM IN YEAST PHYSIOLOGY PERTINENT TO FERMENTATION PROCESSES

Role Examples

Enzyme action

Essential cofactor for numerous (over 300) enzymes, especially those required for glycolysis (including pyruvate decarboxylase)

Cell viability and growth

Magnesium absolutely required for cell division cycle progress in yeast (stimulates DNA synthesis and onset of mitosis). Yeasts have high growth demands for magnesium.

Cell and organelle structure

Membrane stabilization, ribosome and mitochondriastructure

Stress-protectant

Counteracts stresses caused by temperature, osmotic pressure, oxygen free radicals, heavy metals

ANTI-STRESS FUNCTIONS OF MAGNESIUM

Stress Comments

High and low temperatures

Magnesium maintains cell viability when cells are heat or cold shocked. Magnesium prevents synthesis of heat-shock proteins

Oxidative stress

Magnesium counteracts stress caused by reactive oxygen species

Ethanol toxicity

Ethanol increases yeast cell permeability to magnesium. Magnesium increases tolerance to otherwise toxic levels of ethanol

Heavy metals

Magnesium counteracts the toxic effects of Cd, Co, Cu, Al

Growth factor- cannot synthesize essential cellular material from glucose & salts and thus need to be supplied in media. Very small amounts

Common Growth factor

Function

p-aminobenzoate part of tetrahydrofolate, a one-carbon unit carrier

Biotin prosthetic group of carboxylase and mutase

Coenzyme M methyl carrier in methanogenic archaea

Folate part of tetrahydrofolate

Hemin precursor of cytochromes and hemoproteins

Lipoate prosthetic group of 2-keto acid decarboxylase

Nicotinate precursor of pyridine nucleotides (NAD+, NADP+)

Pantothenate precursor of coenzyme A and acyl carrier protein

Pyridoxine precursor of pyridoxal phosphate

Riboflavin precursor of flavins (FAD, FMN)

Thiamine precursor of thiamine pyrophosphate

Vitamin B12 precursor of coenzyme B12

Vitamin K precursor of menaquinone

Auxotrophs– require growth factor

Prototophs– synthesize growth factor

Classification of microorganism on the basis of Nutrition- Nutritional classification

Carbon Hydrogen Oxygen Other elements macro & micro Energy source Electron source

Organic compound electron electron acceptor

Organic compound

Energy

electron acceptor

(reduce)

(oxidize)

(reduce)

(oxidize)

Nutritional classification- based on how microorganism satisfy Carbon, Energy & ElectronCarbon source Autotrophs CO2 sole or principal

biosynthetic carbon source Heterotrophs Reduced, preformed, organic molecules from other

organismsEnergy Sources Phototrophs Light

Chemotrophs Oxidation of organic or

Inorganic compounds

Electron Sources

Lithotrophs Reduced inorganic molecules

Organotrophs Organic molecules

Major* Nutritional Types of MicroorganismsMajor Nutritional

TypesEnergy source

Hydrogen/ electron

carbon source

Representative Microorganisms

Photolithotrophic autotrophy(Photolithoautotrophy)(photoautotrophs)

Light energy

Inorganic hydrogen/electron (H/e–) donor

CO2 carbon source

AlgaePurple and green sulfur bacteriaCyanobacteria

Photoorganotrophic heterotrophy(Photoorganoheterotrophy)(Photoheterotrophs)

Light energy

Organic H/e– donor

Organic carbon source

Purple nonsulfur bacteriaGreen nonsulfur bacteria

Chemolithotrophic autotrophy(Chemolithoautotrophy)(Chemoautotrophs)

Chemical energy source (inorganic)

Inorganic H/e– donor

CO2 carbon source

Sulfur-oxidizing bacteriaHydrogen bacteriaNitrifying bacteriaIron-oxidizing bacteria

Chemoorganotrophic heterotrophy(Chemoorganoheterotrophy)(Chemoheterotrophs)

Chemical energy source (organic)

Organic H/e– donor

Organic carbon source

Protozoa, Fungi,Most nonphotosynthetic bacteria(including most pathogens)

large majority of microorganisms

1) Photoautotrophs 2) Chemoheterotrophs

Photoautotrophs light energy CO2 as their carbon source algae and cyanobacteria employ water as the electron

donor and release oxygen Purple and green sulfur extract electrons from inorganic

donors like hydrogen, hydrogen sulfide, and elemental sulfur.

Chemoheterotrophs organic compounds as sources of energy, hydrogen,

electrons, and carbon Frequently the same organic nutrient will satisfy all

these requirements Yeast, all pathogenic microorganisms are

chemoheterotrophs

other two nutritional classes have fewer microorganisms but often are very important ecologically

Photoheterotrophs purple and green bacteria are photosynthetic organic matter as their electron donor and carbon source common inhabitants of polluted lakes and streams

Chemoautotrophs oxidizes reduced inorganic compounds such as iron,

nitrogen, or sulfur molecules to derive both energy and electrons

Carbon dioxide is the carbon source contribute greatly to the chemical transformations of

elements (e.g., the conversion of ammonia to nitrate or sulfur to sulfate)

Clostridium ljungdahlii

Exceptions-Mixotropic- depending on environment condition