Date of Award

12-2009

Thesis Type

Masters

Document Type

Dissertation

Divisions

Faculty of Science

Department

Institute of Biological Sciences

Institution

Universiti Malaya

Abstract

Decades ago, the Antarctic regions have been exploited for cold-tolerant microorganisms, prospecting various biological benefits, mainly psychrophilic enzymes and bioactive compounds. The first half of the present research aimed to study the occurrence of microfungi in samples of soil taken from Deception Island, Wilhelmina Bay and Yankee Bay, Maritime Antarctica. Attempt made to screen the biodiversity using conventional media and soil plating technique, yielded population of 27 species from the total of 14 soil samples. Of that, 13 fungal species were recorded from Deception Island, 8 from Wilhelmina Bay and 6 from Yankee Bay. Among the genera were Aspergillus, Geomyces and Mucor. Most of the fungal isolates proved to be coldtolerant, as 15 isolates were psychrophilic, 9 mesophilic and 3 psychrotrophic. Nevertheless, there was no positive result regarding the occurrence of thermophilic fungi in the volcanic soil of Deception Island. Second half of the research screened the isolates for the antimicrobial activity. Initially, plug assay (using 4 bacterial and 1 yeast pathogen namely Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans respectively) reported 18 fungal species with antibacterial potential, although no antifungal activity recorded. Subsequently disc diffusion assay was applied (after ethyl acetate extract obtained) using 5 bacterial species and 3 yeast pathogens, namely Candida albicans, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Extract of 10 species (with good results on plug assay) were compared with chemically synthesize antibiotic (Chloramphenicol). However, Chloramphenicol generally recorded higher antibacterial activity with no antifungal activity, while the extract of Hyphomycetes sp.8 does. Otherwise, no significant activities of fungal extracts reported on Gram positive more than Gram negative bacteria or vice versa. Finally, broth microdilution technique was applied to quantify the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) values for future drug development purposes. In the end, Antarctic microfungi found to significantly inhibit wide range of bacterial pathogens and only one species can inhibit yeast pathogens and could be used in the development of new substances for pharmaceutical or agricultural purposes. To our knowledge, to date, there is no published data on the bioactivity of microfungi from Deception Island, Yankee Bay or Wilhelmina Bay.

Initial

khm

Additional Information

Dissertation (M.A.) – Faculty of Science, Universiti Malaya, 2010.

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