Effect of Zinc Oxide (ZnO) to the growth of fungi on Singgora Roof tile.

Singgora roof tile or usually called as clay roof tile was used widely in traditional Malay house. The clay itself has a high moisture absorption rate which makes it an ideal habitat for growth of fungi. Therefore, the addition of the antifungal agent into the clay can inhibit the growth of fungi. To investigate the effect of antifungal, the fungi (Stachybotrys Chartarum) obtained from old Singgora roof tile were cultured using Potato Dextrose Agar (PDA) as the nutrient medium. The single colonies obtained were streak onto empty PDA medium. Six paper discs were distributed evenly on the medium representing each different ZnO weight percentage (0, 5, 10, 15, 20 and 30 wt. %). ZnO solutions were dropped onto the paper disc. The clay samples at a different composition of ZnO were shaped using POP and fired at temperature 800°C for 12 hours to investigate the mechanical and physical properties. Observation for 24, 48 and 72 hours after incubation shows that the optimum antifungal agent for fungi inhibition was at 20 wt. % of ZnO with Zone of Inhibition (ZOI) reached up to 21mm. Density of sample decreases as the porosity increases. Highest porosity was obtained by clay roof tile sample with 30 wt. % ZnO while heaviest density was obtained by sample at 0 wt. % ZnO. Surface morphology of sample also shows the pore size increases as the sample composition increases. In addition, the flexural strength of clay roof tile sample increases with peak value at 10 wt. % reach up to 5.619 MPa. 10 wt.% ZnO have the best ZnO composition to inhibit growth of fungi as well as having a good physical and mechanical properties. The zone of inhibition for fungi was great with average 17 mm diameter. Besides, lower composition ZnO potrays low pore size and crack formation on surface structure and also high flexural strength on mechanical properties.