A study of the growth of Pseudallescheria boydii isolates from sewage sludge and clinical sources on tributyrin, rapeseed oil, biodiesel oil and diesel oil.

The study compared the growth of Pseudallescheria boydii isolates from sewage sludge and from clinical sources on tributyrin, rapeseed oil, biodiesel oil and diesel oil agars. The isolates grew on all substrates tested. The highest growth was observed on rapeseed oil agar, while the lowest on diesel agar. On tributyrin agar, hydrolysis zones were observed around or underneath the colonies. On rapeseed oil agar, no hydrolysis zones were formed, while most isolates formed such a zone on biodiesel oil agar. Rapeseed oil and biodiesel oil stimulated the growth of P. boydii isolates, while tributyrin inhibited fungal growth. The stimulation or inhibition effect of diesel oil was dependent on the specified strain. In clinical isolates, fungal growth and activity were found to be more variable compared to sludge isolates. The data suggest that contamination of the environment with these oils could favor the growth of P. boydii. However, no association was found between the growth and oil utilization by this fungus and its pathogenicity.