Fungi Introduction Difference between fungi and bacteria Classification of fungi Importance of fungi

1. Fungi-moulds and yeast
Prepared by ,
Mr. Snehal Patel,
Assistant Professor,
Sumandeep Vidyapeeth,
Vadodara, Gujarat, India.

2. Content
 Introduction
 Difference between fungi and bacteria
 Classification of fungi
 Importance of fungi

3. Introduction
 Fungi are the group of non-motile eukaryotic organisms which exists
as saprophytes or parasites.
 They posses nuclei surrounded by a nuclear membrane and reproduce
either by budding or by forming spores.
 They have rigid chitinous cell wall.
 Morphologically fungi may be either simple oval cells or long tubular
septate hyphae showing true lateral branching.
 All fungi requires organic compounds for energy and carbon.
 Fungi are aerobic or facultative anaerobic.
 The majority of fungi are saprophytes in soil and water.
 They divide by both unicellular or multicellular.
 The study of fungi is called mycology.

4. Difference between fungi and bacteria
Sr.no Characteristics Fungi Bacteria
1 Cell type Eucaryotic Procaryotic
2 Optimum pH 4 to 6 6.5 to 7.5
3 Optimum temperature 25-300C (saprophytes)
32-370C (parasites)
32-370C (mesophilic)
3 Cell membrane Sterols absent Sterols absent except
mycoplasma
4 Oxygen requirements Strictly aerobic ( moulds),facultative
anaerobic (some yeasts)
Aerobic to anaerobic
5 Light requirement None Some photosynthetic
group occurs
6 Carbon source Organic Inorganic/organic
7 Concentration of sugar in
laboratory media
4 to 5 % 0.5 to 1%
8 Cell wall components Chitin,cellulose or hemicellulose Peptidoglycan
9 Susceptibility to
antibiotics
Sensitive to griseofulvin, Resistant to
penicillins
Resistant to griseofulvin ,
sensitive to penicillins.

5. Classification of fungi
 Depending on cell morphology, fungi can be divided into four classes:
1. Moulds and fleshy fungi
2. Yeats
3. Yeast like fungi
4. Dimorphic fungi

6. 1. Moulds and fleshy fungi
 The body of moulds or fleshy fungus consists of long filaments
of cells joined together, these filaments are called hyphae.
 They are 2 to 10 µm in diameter.
 In most moulds, hyphae contain crosswalls called
septa(septum), which divide the hyphae into distinct,
uninucleate or multinucleate cell-like units. These hyphae are
called septate hyphae.
 In few classes of fungi, the hyphae does not contain septa and
appear as long, continuous cells with many nuclei. These
hyphae are called non-septate hyphae.
 On artificial medium they are seen as a filamentous mould
colony which may be dry and powdery. Eg: Aspergillus niger

8. 2. Yeast
 Yeast are round, oval or elongated unicellular fungi.
 Most of them reproduce by an asexual process called budding.in which a cell
develops a protuberance which enlarges and eventually separates from the
parent cell.
 On the culture they form smooth creamy colonies.
 Eg: Cryptococcus neoformans.

9. 3. Yeast like fungi
 In some yeasts like candida albicans, the bud remains attached to the mother
cell and elongates, followed by repeated budding, forming chains of
elongated cells known as pseudohyphae.
 These can be differentiated from true hyphae because they have a
constriction at the septa are also present at the branching point.
 On solid media moist creamy coloured colonies are produced.

10. 4. Dimorphic fungi
 Some fungi, mainly pathogenic species exhibit dimorphism, i.e two forms of
growth.
 Some fungi can grow either as a mould or as a yeast.
 At 37OC, the fungus yeast like and at 25OC it shows mould like growth.
 Eg: blastomyces dermitidis.

11. Importance of fungi
 Fungi are important source of antibiotics. Eg: Penicillin( Penicillum
notatum), Griseofulvin ( Penicillum griseofulvum ).
 Yeasts and moulds are good source of different enzymes eg: invertase and
zymase obtained from yeast.
 Moulds are used in the production of citric, oxalic and gluconic acid.
 Fungi have been used to alter the texture, improve the flavour, increase
digestibility of natural and processed foods.
 Yeast are used for fermentation purposes in production of beverages and
juices as well as in baking.
 Moulds are also used for production of industrial alcohols by fermentation.
Eg: fusarium species.
 Fungi have capability to breakdown complex organic substrates. This is
essential activity in the recycling of carbon and other elements in the cycle
of life.