Fungal Contamination of Air-conditioned Air Flow with Special Reference to Antifungal Activity of Eight Plant Oil Vapor against Aspergillus Niger

Abstract

Modern buildings without air conditioning are unimaginable. This made them closely related to indoor air quality, especially microbial content. Filters and ducts of AC are colonized by microorganisms, and the air flowing from the AC will carry fungal structures that affect human health. Forty indoor air samples were collected by the plate exposure method from the air current of conditioners in classrooms/secondary school. Samples were collected at the start of operation (S1) and two hours after (S2). This study aimed to isolate and identify of fungi from AC air current, and analysis of the fungal community, as well as in vitro antifungal exam of eight oil vapor against Aspergillus niger. Oils of Hacinathus sp., Cymbopogon citratus, Myrtus communis, Eucalyptus sp., Laurus nobilis, Cinnamon sp., Rosemary officinalis, and Cyperus rotundus were used. Eight fungal genera were listed from a total of 355 fungal colonies: Aspergillus (4 sp.), Penicillium sp, Cladosporium sp, Mucor sp, Alternaria, Geotrichum, Candida, Rhodotorula, besides sterile mycelia. From S1 and S2 samples, 189 colonies (8 genera), and 83 colonies (5 genera) were recognized respectively. Aspergilli showed the highest occurrence of 100% and frequency76.4%. All examined vapor reduced growth of A. niger, C. citratus, Eucalyptus sp., and Cinnamon sp. oils gave the highest significant antifungal activity in comparison with control. It was realized that ACs are an effective source of indoor airborne fungi, and eco-friendly materials have shown significant antifungal activity. They can be the choice of the future.