Aspergillus niger is an opportunistic human pathogen and a strong air pollutant. A study was conducted with 75 different essential oils for the inhibition of hyphal growth and spore formation in Aspergillus niger. Cinnamomum zeylanicum (bark), Cinnamomum zeylanicum (leaf), Cinnamomum cassia, Syzygium aromaticum and Cymbopogon citratus were the top five essential oils which demonstrated marked inhibitory effect against hyphal growth and spore formation of A. niger. The chemical composition of these five most active essential oils was investigated by gas chromatography-mass spectra (GC-MS). Most of the other essential oils were found challenging to combat A. niger, suggesting their use as strong aroma therapeutic agents.

The objective of this study was to analyze mycelial growth under different culture conditions and antimicrobial activity of Pleurotus ostreatus (Jacq.: Fr.) Kumm. (DPUA 1533) and P. ostreatus (Jacq.: Fr.) Kumm. cv. Florida (DPUA 1534) against fungi and bacteria of medical importance. The growth of Pleurotus species was evaluated in natural and complex media, with and without light, at 25°C and 28°C for 8, 15, and 30 days. Candida albicans (DPUA 1336), Cryptococcus laurentii (DPUA 1501), Aspergillus flavus (DPUA 1836), Escherichia coli (DAUPE 224), and Mycobacterium smegmatis (ATCC 607) were used to test antibiosis. Under all growth conditions in vitro, Pleurotus species evidencedgrowth and high density of mycelia on potato dextrose agar and Sabouraud agar with yeast extract; mycelial growth but lesser mycelial density was observed on rice bran extract agar. Organic mycelial extracts of Pleurotus species exhibited potential antibacterial and antifungal activity, and were selective for the tested microorganisms.