This document discusses the nutrition and growth conditions of fungi. It explains that fungi can be saprophytic or parasitic and obtain nutrients from dead or living organic matter. The key nutrients fungi need are carbon, nitrogen, phosphorus, potassium, magnesium, and sulfur. Glucose and other sugars serve as the best carbon sources while ammonium, nitrates, and amino acids provide nitrogen. Fungi grow best between 0-30°C, at a pH of around 6, and do not require light for growth though some need it for sporulation.

1. MYCOLOGY
(MIC 206)
VEGETATIVE GROWTH

2. NUTRITION

3. NUTRITION
1) Saprobe or Parasite
• They are either saprophytic or parasitic.
• An obligate saprobe: incapable of causing
disease on living organisms as they live on
dead organic matter.
• A facultative parasite or facultative
saprobe: cause disease or live on dead
organic matter depending on
circumstances.
• An obligate parasite must only feed on
living organisms.

4. NUTRITION
2) Nutrients
 Fungi do not possess chlorophyll and are not
able to make their own food.
 But if given carbohydrates (e.g. glucose /
maltose), most of them can make their own
proteins from organic or inorganic sources.
 Most fungi need C, O, H, N, P, K, Mg, S, B, Mn,
Cu, Mo, Fe, Zn and Ca (not so for all fungi).
 Fungi store excess foods in the form of
glycogen or lipids.

5. Media for growth of fungi
In addition to water, a complete medium for the
growth of a fungus must have these constituents :
a) a suitable organic substance as a source of
carbon
b) a source of nitrogen
c) appreciable amounts of certain organic ions
d) traces of other inorganic ions
e) low concentrations of organic growth factors

6. Carbon source
Best carbon source: Glucose, frequently the largest
constituent of a liquid medium for fungal growth.
Glucose is a carbon source which nearly all fungi can
absorb and utilize.
Two other sugars which are generally suitable are
sucrose and maltose.
Most fungi can use starch and many use cellulose.

7. Nitrogen source
All fungi can utilize a suitable organic supply of
nitrogen. Best Nitrogen sources: Ammonium and
nitrates compounds.
Given as peptone, an amino acid (e.g. glutamic
acid) or an amide (e.g. asparagine).
Limited number of fungi can make use of nitrogen in
inorganic combination such as ammonium or nitrate
ion.
Organic substances such as peptone or asparagine
can supply both the carbon and nitrogen needs of a
fungus.

8. Inorganic substances
Inorganic substances needed are potassium,
phosphorus or phosphates, magnesium and
sulphur or sulphate in significant amounts.
But calcium (which is needed by green plants) is
needed by only some fungi.
Other inorganic substances include iron, zinc,
copper, manganese and molybdenum which are
needed in only a few parts per million. They
appear to contribute to the structure of essential
enzymes.

9. Organic growth factors
 Organic growth factors, mainly vitamins are required in
small amounts.
 These same vitamins are needed by all other organisms.
 These are either provided by the external source or
synthesized by the organism.
 Some are completely self-sufficient. Others require an
external source of one or more vitamins.
 The two most often needed vitamins are thiamine (vitamin
B1) and biotin.
 For example, in the complete absence of thiamine,
Phycomyces cannot grow.

10. Organic components
 The organic component need not be in a soluble form,
although only substances in solution can be absorbed by a
hypha.
 Starch and cellulose are often supplied as the organic food
for a fungus in pure culture. Their utilization depends on the
production of extracellular enzymes (exoenzymes) which
are transferred out from the hyphal tips.
 Starch is converted to soluble glucose under the influence
of excreted amylase.
 Sucrose although soluble (usually used in culture media)
does not pass readily into the living hypha. Before
absorption, it is normally converted into its component
hexose by extracellular invertase.

11. Enzymes
A large number of fungi produce extracellular cellulases
which allow fungi to make use of cellulose.
Some examples of these type of fungi are Trichoderma
reesei and Trichoderma viride.
These fungi produce 3 groups of enzymes for this purpose:
 endo β (1-4) glucanase or EG,
 exo β (1-4) glucanase or cellobiohydrolase or CBH
 cellobiose oxidase (oxidative enzyme).

12. GROWTH
CONDITIONS

13. GROWTH CONDITIONS
1) Temperature
 Most fungi grow best between 0oC to 30oC of
which the optimum temperature range is 20-30oC.
 Thermophilic species can grow to above 50oC or a
minimum of 20oC.
2) pH
 The pH is pH6.
3) Light
 Light is not required but some light is essential for
sporulation in many species.
 Important role in spore dispersal.