SCREENING OF ANTIBIOTIC PRODUCING ACTINOMYCETES FROM THE SOIL SAMPLES AND ANTIBACTERIAL ACTIVITY IN VARYING SODIUM NITRATE CONCENTRATION
Date
2022-08-08
Authors
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Publisher
Amrit Campus
Abstract
Actinomycetes are gram positive filamentous, slow growing bacteria, best known to produce
antibiotic. The aim of this study was to screen antibiotic producing actinomycetes and determine
its antibiotic activity against ATCC cultures at different gradient of NaNO3. This study was
carried out from March 29 to April 28, 2022. Thirty collected samples were collected and
transported and processed in Amrit campus. Primary and secondary screening were performed
by perpendicular streaking and agar well diffusion method respectively. Characterization and
identification of the isolated actinomycetes were performed. From thirty collected samples,
twenty-eight samples were actinomycetes. Only two samples were antibiotic producing
actinomycetes MI410 -3 and NP110 -2 showed antibacterial activity against ATCC cultures viz:
S. aureus 43300, E. coli 35218, E. coli 25922 and Klebsiella 700603 in primary screening.
Antibiotic was produced by sub-merged state fermentation with varying concentration of
NaNO3 and secondary screening was done by agar well diffusion against ATCC cultures in
comparison to standard streptomycin (100 µg/mL).
In comparison to standard streptomycin (100 µg/mL) extract MI410-3 with 1% NaNO3 was
effective only against E. coli 25922 while NP110-2 with 0.5% NaNO3 against E.coli 35218
(14.67mm), E.coli 25922 (19.67mm) and S. aureus 43300 (17mm) whereas NP110-2 has also
shown antibacterial effect with 1.5% NaNO3 against E. coli 35218 (13mm), Klebsiella spp.
ATCC 700603 (11.5mm) and S. aureus 43300 (12.5mm).
Statistically, there is significant difference at 5% level of significance between the sample
concentration at 0.5% of NaNO3 (.001, P<0.05) and 1.5% of NaNO3 (0.024, P<0.05) in
antimicrobial activity. However, there is no significant difference at 5% level of significance
between the sample concentration at 1% (0.356, P>0.05). The isolated actinomycetes was
presumed as Streptomyces spp. Both MI410-3
and NP110-2
(7.14%) showed antibacterial
activity against cultures in primary screening. The indigenous species of actinomycetes, isolated
from various places of Kathmandu valley can be used in industrial production of antibiotics
which can help in economic growth of Nepal.
Description
Keywords
Agar well diffusion, Antimicrobial activity, ATCC cultures, NaNO3, Streptomyces spp.