(1) carbon source

Definition: Any nutrient source that can provide carbon for microbial nutrition.

Microbial carbon source spectrum:

Carbon source: organic carbon source: starch, glucose, etc. Inorganic carbon source: Na2CO3, etc. Secondary growth of glucose and lactose.

For heterotrophic microorganisms, carbon source is also energy.

(2) Nitrogen source substance

Definition: Any nutrient source that can provide nitrogen for microbial nutrition.

Function: nitrogen source. Generally not used as an energy source.

Microbial nitrogen source spectrum:

Quick-acting nitrogen source and slow-acting nitrogen source

Physiological alkaline, acidic and neutral salts

Nitrogen source: organic nitrogen source: peptone, soybean flour, corn steep liquor, inorganic nitrogen source: NH4NO3, (NH4) 2SO4, quick-acting nitrogen source and slow-acting nitrogen source.

There is an obvious boundary in terms of the energy that microorganisms can use.

Amino acid autotroph:

Amino acids are not needed as nitrogen sources. They can synthesize all amino acids from simple non-amino acid nitrogen sources (such as urea, ammonium salt, nitrate and nitrogen), including all animals and a large number of heterotrophic microorganisms.

Amino acid heterotrophs:

Microorganisms that need to absorb ready-made amino acids from the outside as nitrogen sources. They contain all green plants and a variety of microorganisms.

(3) Energy

Definition: Chemical substances or radiant energy that can provide an initial energy source for microbial life.

Chemical energy: organic matter: energy to transform heterotrophic microorganisms.

Inorganic matter: the energy source of chemoautotrophic microorganisms

The carbon source of heterotrophic microorganisms is also energy.

power spectrum

Chemical substance

Light energy: the energy of photoautotrophic and photoheterotrophic microorganisms.

function

Single function: radiant energy

Dual function: reducing inorganic nutrients, such as NH4+, is both an energy source and a nitrogen source for nitrate bacteria.

Three major functions: N C H O nutrients are often the energy source, carbon source and nitrogen source of heterotrophic microorganisms.

Growth factor (growth factor)

A class of organic substances necessary for normal metabolism of microorganisms cannot be synthesized by simple carbon and nitrogen sources.

Category: vitamins, amino acids, nucleotides, folic acid, etc.

Function: needed for coenzyme or enzyme activation.

Sources of growth factors in the culture medium: yeast extract, corn steep liquor, wort, etc. (multivitamins).

(5) Inorganic salts

The elements with the required concentration of 10-3- 10-4M are macroelements.

The required concentration is 10-6- 10-8M.

Main functions: constitute bacterial components, constitute or maintain enzyme activity through enzyme active groups, adjust osmotic pressure, pH .Eh, chemoautotrophic microbial energy, etc.

Inorganic salts: provide mineral elements and trace elements.

(6) water

Existence state: free state (solvent) and bound state (structural composition)

Physiological function: composition, reaction medium, material transport medium, good conductor of heat.

Water is a good solvent, biochemical reaction is carried out in water, and the specific heat of water is large.