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.

The growth of proteolytic microorganisms affects keratinolytic fungi in sewage sludge.

The present study was to demonstrate the effect of proteolytic microorganisms on the growth and composition of keratinolytic fungi in sewage sludge. In model experiments, the 3-layer hair baiting method (layer I--sludge solidified with agar medium; layer II--agar medium layer covering layer I; and layer III--hair) was used. The agar medium contained increasing peptone concentrations (0, 0.5, 1, 2, 5 and 10 g/L). The number of occurrences along with other fungal growth indices increased up to the peptone concentration of 2 g/L. Upon the highest peptone concentration (10 g/L), the abundant growth of sludge proteolytic bacteria and fungi inhibited the growth of most keratinolytic fungi. Under these conditions, only Scopulariopsis brevicaulis, the fungus of epidemiological concern, was able to penetrate the medium and to attack hair. The antibiotics (chloramphenicol and actidione in concentrations of 100 and 500 mg/L) added to the peptone agar inhibited, to a high degree, the growth of sludge proteolytic microbiota and enabled many keratinolytic fungi to grow.

[A study of the growth and enzymatic activity of Microsporum gypseum and Trichophyton ajelloi isolates from sewage sludge]. / Badania wzrostu i aktywnosci enzymatycznej szczepów Microsporum gypseum i Trichophyton ajelloi wyizolowanych z osadów sciekowych.

The study was to compare growth and enzymatic activity of Microsporum gypseum and Trichophyton ajelloi isolates from sewage sludge. Agar media and the API-ZYM test were used. The isolates showed weak gelatinase, catalase and urease activities and did not produce cellulase, pectate lyase and polygalacturonase. In some strains poor amylase and DNA-se activities were observed. No strain was able to hydrolyze casein. The strains were found to hydrolyze tributyrin, rapeseed oil and Biodiesel oil and to grow on Diesel oil medium. On the medium containing tributyrin and on the media with rapeseed oil and Biodiesel oil additions, inhibition and stimulation of fungal growth was observed, respectively. Diesel oil did not affect the growth of these fungi. The growth and enzymatic activity of M. gypseum was found to be better than the growth and activity of T. ajelloi. Higher enzymatic activity can be associated with the pathogenicity of M. gypseum.

Sewage sludge open-air drying affects on keratinolytic, keratinophilic and actidione-resistant fungi.

The study was to demonstrate the effect of sewage sludge open-air drying on the quantitative and qualitative composition of keratinolytic/keratinophilic and actidione-resistant fungi. The sludge was being dried for up to thirty days (on average fourteen days) at 25-30'C. The composition of these fungi was determined with the hair baiting method along with the dilution method, using the Wiegand medium supplemented with chloramphenicol (100 mgiL) and actidione (500 mg/L). The open-air drying altered the composition of keratinolytic fungi and considerably increased the population of keratinophilic and actidione-resistant fungi in the sludge. This phenomenon can be explained with that the drying process was associated with slow sludge moisture decrease, sludge laceration due to crumbling and the subsequent improvement of sludge aeration and organic matter biodegradation conditions. A considerable increase of fungal populations can be expected in sludges being dried in drying beds at wastewater treatment plants and in sludge-amended soils. Two sludge opportunistic fungi, i.e. Microsporum gypseum and Pseudallescheria boydii, require special attention from the epidemiological point of view. Sludge land applications may increase the number of these fungi in the environment and the subsequent risk to public health posed by them.