TO EVALUATE ANTIMICROBIAL ACTIVITY OF DIFFERENT SOIL BACTERIA,

1. TO EVALUATEANTIMICROBIALACTIVITYOF DIFFERENTSOIL
BACTERIA
GOEL & COMPANY LUDHIANA
Prop: CHETAN KUMAR GOEL
ADD: S.C.O.NO- 03, S.B.S.NAGAR, DUGRI
DHANDRA ROAD, LUDHIANA-141013

2. ABSTRACT
• Antimicrobial activity of bacterial strains isolated from five soil samples of
Ludhiana were evaluated.
• At specific dilution bacterial colonies with clear zone of inhibition were
observed which retarded the growth of other organisms. It may be due to
production of inhibitory substance viz. organic acids, toxins or antibiotics.
INTRODUCTION
Ever since the mankind started suffering from ailments, the quest for finding
remedies to treat the disease started. The science of antibiotics has remained and
will remain for many years.
Microbial natural products still appear the most promising source of future
antibiotics that the society is expecting.
Antibiotics are produced by bacteria, fungi, actinomycete, algae, lichens etc.
Bacteria are easy to isolate, culture, maintain and to improve their strains. the best
source of microbes is soil. Living body of soil contains microbes that play important
role in release of nutrients and carbon dioxide. The microbes especially bacteria
that reside in soil have ability to produce biologically active secondary metabolites
such as organic acids, toxins or useful antibiotics. In their natural habitat they use
the antibiotic produced as protective substances inhibiting growth of other
bacterial species.

3. To determine antimicrobial activity of different soil bacteria
METHOD
In a systematic program five soil samples of soil were collected vfrom
different areas of Ludhiana city. Soil sample were collected using
clean and dry bag along with sterile spatula. The soil samples were air
dried and added 10g of it in 90ml sterile water to make soil
suspension (10-1)
Now the 10-1 suspension was serially diluted by successive transfer of
dilution to 9ml water blanks. In this way 10-1 – 10-7 were prepared.10 -
4 – 10 -7 dilution were used for isolation of bacteria
Transferred the 1 ml aliquots from 10 -4 dilution to three Petri plates.
Agar medium was added to these plates and upon solidification of
media , plates were incubated at 28 o C for 3-4 days
Screened organisms formed halo zones or the inhibtory zones around
other species

5. RESULT
Clear zone of inhibtion were observed which regarded the growth of other organisms
were observed. It may be due to the production of inhibitory substances viz.
organic acids, toxins, antibiotics and other biologically active secondary
metalbolites