Desi Eka Sapta Ahmad (2013) Isolation and screening for antibacterial activity of actinomycetes from antarctic soils. Masters thesis, Universiti Malaysia Sabah.
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Abstract
South Shetland Islands are a group of Antarctic islands where a number of novel Actinomycetes have been isolated. Actinomycetes are aerobic, slow growing Grampositive bacteria that form filamentous branching hyphae with asexual spores widely spread in nature. The aims of this study are (i) to isolate Actinomycetes from Antarctic soil samples, (ii) to screen antibacterial activity of the isolated colonies and (iii) to characterize the morphology of Antarctic Actinomycetes. Isolation of the bacteria was carried out using Actinomycetes Isolation Agar, Nutrient Agar and Oatmeal Agar supplemented with Cycloheximide and Kanamycin at 12°C, 20° C and 28° C. Pure cultures were used for the subsequent analyses. Gram staining and Methylene blue staining were performed on the isolates and all the isolates were found to be filamentous branching hyphae and identified as Gram positive. The morphology of colonies is varying from white, grey, brownish and yellow colour and appeared to be convex, concave or flat surface. Antibacterial screening was determined using perpendicular streak/cross streak method as primary screening and agar well test as the secondary screening. A total of fifty-five actinomycetes strains were isolated from Antarctic soils. All fifty-five isolates were tested for antibacterial activity against six common foodborne pathogens. After the primary and secondary screening only 23.63 % or thirteen , AN3, AN4, AN6, AN7, AN8, AN9, ANll, AN13, AN26, AN27, AN28, AN29 and AN30 of the total fifty-five strains showed inhibition potential against one or more out of the six tested pathogen strains. 16.36 % or nine, AN3, AN4, AN6, AN9, AN11, AN13, AN27, AN29 and AN30 of the isolates inhibited Enterobacter cloacae meanwhile 12. 73 % or 7, AN3, AN7, ANS, AN11, AN13, AN26 and AN28 isolates inhibited BaCJ'l!us cereus and 5.45% or three, AN3, AN11 and AN13 of the isolates inhibited both £cloacae and B.cereus which indicated broad-spectrum. However no inhibitions were observed on other four pathogens, Escherichia coll Salmonella typhl Vibrio parahaemolyticus and Klebsiella pneumoniae. This implies that Antarctica harbours Actinomycetes which have bioactive compounds that can inhibit the growth of several foodborne pathogens and a good source of antibacterial compounds. The potential isolates can later be identified using molecular for further analysis.
| Item Type: | Thesis (Masters) |
|---|---|
| Keyword: | Actinomycetes, Antarctic soil bacteria, South Shetland Islands, Antibacterial activity |
| Subjects: | Q Science > QK Botany > QK1-989 Botany > QK504-(638) Cryptogams |
| Department: | INSTITUTE > Biotechnology Research Institute (BRI) |
| Depositing User: | DG MASNIAH AHMAD - |
| Date Deposited: | 17 Jun 2025 11:26 |
| Last Modified: | 17 Jun 2025 11:26 |
| URI: | https://eprints.ums.edu.my/id/eprint/44146 |
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