Besides macroscopic plants and animals, microbes are
the major components of biological systems on this earth.
You have studied about the diversity of living organisms
in Class XI. Do you remember which Kingdoms among
the living organisms contain micro-organisms? Which are
the ones that are only microscopic? Microbes are present
everywhere–in soil, water, air, inside our bodies and that
of other animals and plants. They are present even at sites
where no other life-form could possibly exist–sites such
as deep inside the geysers (thermal vents) where the
temperature may be as high as 100
0
C, deep in the soil,
under the layers of snow several metres thick, and in highly
acidic environments. Microbes are diverse–protozoa,
bacteria, fungi and microscopic animal and plant viruses,
viroids and also prions that are proteinacious infectious
agents. Some of the microbes are shown in Figures 10.1
and 10.2.
Microbes like bacteria and many fungi can be grown
on nutritive media to form colonies (Figure 10.3), that can
be seen with the naked eyes. Such cultures are useful in
studies on micro-organisms.
CHAPTER 10
MICROBES IN HUMAN WELFARE
10.1 Microbes in Household
Products
10.2 Microbes in Industrial
Products
10.3 Microbes in Sewage
Treatment
10.4 Microbes in Production of
Biogas
10.5 Microbes as Biocontrol
Agents
10.6 Microbes as Biofertilisers
2021–22