TO EVALUATE ANTIMICROBIAL ACTIVITY OF DIFFERENT SOIL BACTERIA

GOEL & COMPANY LUDHIANAProp: CHETAN KUMAR GOEL

ADD: S.C.O.NO- 03, S.B.S.NAGAR, DUGRI DHANDRA ROAD, LUDHIANA-141013

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.

INTRODUCTIONEver 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.

To determine antimicrobial activity of different soil bacteria

METHOD

In a systematic program five soil samples of soil were collected vfromdifferent 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 bacteriaTransferred 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 daysScreened organisms formed halo zones or the inhibtory zones around other species

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