This slide is created by Binod Pokhrel, Student of B.V.Sc & A.H at Agriculture and Forestry University.

1. DATE : 2016/08/12
GROWTH AND
NUTRITION OF
FUNGI
Binod Pokhrel
B.V.Sc & A.H
AFU,Rampur

2. Growth
Growth is defined as the
irreversible increase in the dry
mass of an organism. It is
brought about by an increase in
cell size or number.

3. How growth takes place in Fungi?
 Mycelial fungi - extension growth of hyphae(tip).
 Unicellular fungi (e.g. yeasts) - increase in individual cell volume.
 Yeast like fungi grow partly as yeast and partly as chain of
elongated budding cells joined end to end .
 Moulds or filamentous fungi with multiple cells forming typically a
thread-like mass with many branches grows by branching and tip
elongation

5. Optimal condition for growth
 Presence of water: 80–90% of the fungi is
composed of water by mass, and requires
excess water for absorption due to the
evaporation of internally retent water.
 Presence of oxygen
 Neutral-acidic pH : Optimum pH 5.0

6. Contd…
 Low-medium temperature: ranges between 1 °C and
35 °C, with optimum growth at 25 °C.
 The majority of nutrients must be able to provide carbon,
proteins, vitamins and cases, ions. Due to the carbon
composition of the majority of organisms, dead and
organic matter provide rich sources of disaccharides and
polysaccharides such as maltose and starch and of the
monosaccharide glucose.
 In terms of nitrogen-rich sources, saprotrophs require
combined protein for the creation of proteins, which is
facilitated by the absorption of amino acids, and usually
taken from rich soil. Although both ions and vitamins are
rare, thiamine or ions such as potassium, phosphorus, and
magnesium aid the growth of the mycelium.

7. How Fungi is grown on lab?
1. Liquid bath culture
2. Liquid continuous culture
3. Culture on solid media

8. Liquid bath culture
If we wanted to
estimate the growth
of a mycelial fungus
growing in a LIQUID
medium, we might
first have to filter off
the liquid medium
and then determine
the dry mass of
the mycelium.

9. Liquid continuous culture
An alternative to the liquid batch
culture system is CONTINUOUS
CULTURE in a liquid medium:
 This involves the CONTINUOUS
ADDITION OF FRESH CULTURE
MEDIUM to the vessel and the
WITHDRAWAL (by means of an
overflow devise) of a corresponding
volume of OLD, SPENT MEDIUM,
which will contain some of the
microbial cells.
 The apparatus used is called
a chemostat

10. Solid Media
 While it's relatively easy
to determine the
biomass of a fungus
growing in a liquid
medium, it's more
difficult to estimate
biomass when a fungus
is growing in all three
dimensions over and
through a solid
medium.
 For this reason we
usually express the
growth of a colony in
terms of the RADIAL
EXTENSION OFTHE
COLONY (i.e. we
measure colony radius).

11. NUTRITION In FUNGI
 ALL fungi are CHEMOHETEROTROPHIC (chemo-
organotrophic) - synthesising the organic
compounds they need for growth and energy from
pre-existing organic sources in their environment,
using the energy from chemical reactions.
 They lack chlorophyll pigments and are incapable of
photosynthesis.
 Fungi absorb their food, rather than ingesting it as
their protoplasm is surrounded by rigid wall.
 SMALL MOLECULES (e.g. simple sugars, amino
acids) in solution can be absorbed directly across
the fungal wall and plasma membrane..

12. Contd..
 LARGER, MORE COMPLEX MOLECULES (e.g. polymers such
as polysaccharides and proteins) must be first broken down
into smaller molecules, which can then be absorbed.This
degradation takes place outside the fungal cell or hypha and is
achieved by enzymes which are either released through or are
bound to the fungal wall. Because these enzymes act outside
the cell they are called extracellular enzymes.
 Since water is essential for the diffusion of extracellular
enzymes and nutrients across the fungal wall and plasma
membrane, actively growing fungi are usually restricted to
relatively moist (or humid) environments.
 Fungi are more resistant to high osmotic pressure than
bacteria.
 Fungi require less nitrogen than bacteria to grow and can grow
at PH of 5.

13. Process of Nutrition intake
 As matter decomposes within a medium in which a
saprotroph is residing, the saprotroph breaks such matter
down into its composites.
 Proteins are broken down into their amino acid composites
through the breaking of peptide bonds by proteases.
 Lipids are broken down into fatty
acids and glycerol by lipases.
 Starch is broken down into pieces of simple disaccharides
by amylases.
 These products are re-absorbed into the hypha through the
cell wall via endocytosis and passed on throughout the
mycelium complex. This facilitates the passage of such
materials throughout the organism and allows for growth
and, if necessary, repair.

14. Thanks for
your
concentration