Screening for Antimicrobial Activities in Mycobionts Isolated From Lichens Collected From Palm Trees in UNIMAS Campus

• Main Author: Ng, San Hui
• Format: Final Year Project Report
• Language: English
• Published: Universiti Malaysia Sarawak, UNIMAS 2010
• Subjects: Q Science (General)
• Online Access: http://ir.unimas.my/id/eprint/7901/4/Ng%20San%20Hui%20ft.pdf; http://ir.unimas.my/id/eprint/7901/

The emergence and spread of multi-drug resistant bacteria have become a global threat to the public health. This is due to the ineffectiveness of life-saving antibiotics. Lichens are receiving great attention from researchers as significant new sources of bioactive substances since their secondary metabolites are reported to have antimicrobial activities. This study was done to screen the antimicrobial activities of mycobionts isolated from lichens collected from palm trees in UNIMAS campus. A total of 28 fungal isolates were subjected to preliminary screening by agar overlay technique against three Gram negative bacteria, Enterobacter aerogenes, Escherichia coli, Salmonella typhi and one Gram positive bacteria, Staphylococcus aureus. Eight fungal isolates showed inhibitory effect towards Gram negative bacteria, but none inhibited Gram positive bacteria. All the eight fungal isolates were subjected to secondary screening on V8 juice agar plates for further testing. Only six of the fungal isolates formed zones of inhibition against the test bacteria. Extraction using methanol solvent was performed on the six fungal isolates to extract the active secondary metabolites. From the result of antimicrobial activity screening by Kirby-Bauer disc diffusion method, methanol extracts of L2(2), L2(3), L2(5) and L10(2) isolates formed zones of inhibition against E. aerogenes. The largest diameter of the zone of inhibition was observed for L10(2) which was 15.5mm, while the smallest was 9.5mm for L2(2). Macroscopical and microscopical observations using slide culture technique revealed that the fungal isolates L2(2), L2(3) and L2(5) possessed similar morphological characteristic and implied to belong to the same genus while L10(2) was a different fungi.