Chaetothyrialean fungi from aromatic hydrocarbon-polluted environments of Iran

Abstract

In this study we aimed to isolate and characterize chaetothyrialean mitosporic fungi from natural oil fields in Iran. Soil samples were collected from areas of Khuzestan, Bushehr, and Kohgiluyeh and Boyer-Ahmad provinces in Iran and processed with the oil flotation method. They yielded numerous colonies of dematiaceous hyphomycetes. Among them, fifteen isolates were identified as members of the Chaetothyriales based on morphology and DNA sequences of the Internal Transcribed Spacer (ITS) region of the ribosomal RNA gene complex. These included thirteen isolates of Exophiala xenobiotica and two of Phialophora americana. Some of these strains were tested for assimilation of benzene, toluene, ethylhenzene, and xylene (BTEX) gases and were able to grow exposed to these gases. These isolates had an optimum growth temperature below 30 degrees C, which makes them potential candidates for bioremediation of soils contaminated with aromatic compounds. Exophiala xenobiotica and P americana are reported for the first time from natural oil fields in Iran.