This document discusses the nutritional requirements of bacteria. It divides bacteria into two groups - autotrophs, which can synthesize their own nutrients from carbon dioxide and nitrogen, and heterotrophs, which require preformed organic compounds. The minimal nutrient requirements for all bacteria include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. Many pathogenic bacteria are heterotrophs that have lost the ability to survive without external growth factors supplied in their environment.

1. BACTERIAL NUTRITION
MAN BAHADUR RANA
BPH
ACAS,NEPAL

2. CONTD..
The minimal nutrition requirements comprise
of the sources of C, N, H, O and some
inorganic salts.
On the basis of synthesizing
capability bacteria are divided into two basic
groups.
Autotrophs: Bacteria which can synthesize
their essential metabolites (organic
compound) from the atmospheric CO2 and
nitrogen are called autotrophs or lithotrophs.

3. CONTD..
Heterotrophs: Bacteria which cannot synthesize
their own metabolites but required preformed
organic compound for growth are known as
heterotrophs.
Autotrophs
Photoautotrophs Chemoautotrophs

4. CONTD…
Photoautotrophs: Autotrophs that obtain
energy from the sunlight.
Chemoautotrophs: Those utilising inorganic
compound for oxidation.
- Majority of pathogenic bacteria are
heterotrophs and parasitic.
- They have lost the biosynthetic mechanism
required for free living existence in rough
environment of soil and water for which
growth factors are required to be supplied
from outside.

5. NUTRITIONAL REQUIREMENTS.
 Essential elements:
The most important elements
necessary for synthesis of bacterial structural
component (carbohydrate, lipid, protein, nucleic
acid) are H, O, C, N.
 In addition to these elements, phosphorus and
sulphur are also required for bacterial growth.

6. CONTD..
 Hydrogen and Oxygen:
- available from water added to culture medium.
 Carbon and Nitrogen:
- Carbohydrate(usually sugar) is the principal
source of carbon which is degraded by other
bacteria either by oxidation or fermentation.

7. CONTD..
 Nitrogen:
- major component of protein and nucleic acid.
- its main source is ammonia, usually in the form of
ammonium salt.
- the ammonium salt is made available either from
the environment or it may be produced by
deamination of amino acid.

8. CONTD..
 Sulphur and Phosphorus:
- most bacteria use So4 (sulphate) as a
sulphur source.
- Phosphorus is required as a component of
nucleic acid, ATP, coenzymes NAD,
phospholipids.
 Mineral source:
- These are potassium, calcium,
magnesium, iron, copper, cobalt,
manganese and zinc required in trace
amount for enzyme function.

9. CONTD..
 Organic growth factors:
- some bacteria requires organic compound
which cannot be synthesized by
themselves. These are called growth factors
or bacterial vitamins.
- in many cases the growth factors are
identical with vitamins belonging to B
groups- thiamine, riboflavine, nicotinic acid,
pyridoxin, folic acid, vitaminB12