SEBATIAN ANTIBAKTERIA DARIP ADA BAKTERIA MARIN TEMPATAN, Vibrio ruber (S2Al)
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Date
2004-06
Authors
NOORDIN, WAN NORHANA
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Abstract
The impact of marine microorganisms on the discovery of novel bioactive
metabolites has been proven by the increasing number of published articles. Despite
the vast potential of this field, research in Malaysia is still at an early stage. This study
was carried out to assess the potential of local marine microorganisms as antibiotic
producer and later to study the growth and production of antibiotic compounds by a
selected strain. From the total of 160 marine microorganisms (134 bacterial, 9
actinomycetes, 3 fungal and 14 yeast strains) isolated from marine samples collected
around Peninsular Malaysia waters, 78 (48.7%) exhibited antimicrobial activities.
Majority of the positive isolates (35.0%) had activities to at least five test
microorganisms while only a small percentage (1.9%) had a broad spectrum
antimicrobial property with activities to more than 20 test m' icroorganisms. Isolates
which had the most antimicrobial activities were isolated from molluscs (65.0%) and
sponges (58.8%), while the sediment (15.8%) samples contributed the least. The red
pigmented isolate, S2A1 was chosen as antibacterial producer and Methycillin
resistant Staphylococcus aureus (MRSA ATCC 33591) as test microorganism for
further studies. S2Al, was later identified as Vibrio ruber through subunit 16
I
ribosomal ribonucleic add (16S rRNA) sequencing. The optimisation of medium
composition and cultural conditions of S2Al revealed that the optimum cultural
conditions were medium with initial pH of 7.0, temperature of (28 ± 2)°C, agitation
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rate of 100 rpm in semi solid medium (0.4% agar) for 48 hours. While the optimum
medium composition was (w/v) 0.3% yeast extract, 0.3 %peptone, 0.1% starch, 0.1%
proline, 0.4% bacteriological agar, 0.02% KBr, 0.02% ZnS04.?H20, prepared with
100% fresh seawater. After optimization, production of antibacterial compound(s) by
v. ruber S2Al was increased 9.1-58.1% and growth (6.5-14.3)%. Characterisation of
crude antibacterial extract of V ruber S2Al showed that it was stable at wide range of
temperature (20-90)°C, pH (3-11) and storage (at 4°C for more than 2 months).
Meanwhile observation under Transmission Electron Microscope (TEM) and
Scanning Electron Microscope (SEM) indicated that crude antibacterial extract from
V. ruber S2A1 showed bactericidal activity against MRSA cells at high concentration.
and bacteriostatic activity at low concentration with possible action on the MRSA cell
wall.
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SEBATIAN ANTIBAKTERIA DARIP ADA BAKTERIA MARIN TEMPATAN