Cladophialophora Psammophila, a Novel Species of Chaetothyriales with a Potential Use in the Bioremediation of Volatile Aromatic Hydrocarbons

Cladophialophora is a genus of asexual black yeast-like fungi with one-celled, hydrophobic conidia which is predicted to have teleomorphs in the ascomycete genus Capronia, a member of the order Chaetothyriales. Cladophialophora species are relatively frequently involved in human disease ranging from mild cutaneous lesions to cerebral abscesses. Although the natural niche outside humans is unknown for most opportunistic Cladophialophora species, the fungi concerned are rarely isolated from environmental samples such as dead plant material, rotten wood, or soil. The objective of the present paper is to describe a novel species of Cladophialophora which was isolated from soil polluted with benzene, toluene, ethylbenzene, and xylene (BTEX). It proved to be able to grow with toluene and other related alkylbenzenes as its sole carbon and energy source. This strain is of interest for the biodegradation of toluene and other related xenobiotics under growth limiting conditions, particularly in air biofilters, dry and/or acidic soil. A preliminary genetic analysis using multilocus sequencing typing (MLST) and amplified fragments length polymorphism (AFLP) showed that this fungus was closely related to the pathogenic species Cladophialophora bantiana, sharing a C. bantiana-specific intron in SSU rDNA. However, it was unable to grow at 40°C and proved to be non-virulent in mice. The clear phylogenetic and ecophysiological delimitation of the species is fundamental to prevent biohazard in engineered bioremediation applications.