The diversity of fungi in aerobic sewage granules assessed by 18S rRNA gene and ITS sequence analyses

Aerobic sewage granules are dense, spherical biofilms, regarded as a useful and promising tool in wastewater treatment processes. Recent studies revealed that fungi can be implemented in biofilm formation. This study attempts to uncover the fungal diversity in aerobic granules by sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer regions. For this purpose, appropriate PCR and sequencing primer sets were selected and an improved DNA isolation protocol was used. The sequences of 41 isolates were assigned to the taxonomic groups Pleosporaceae, Xylariales, Theleobolaceae, Claviceps, Aureobasidium, Candida boleticola, and Tremellomycetes within the fungi. It turned out that the fungal community composition in granules depended on the wastewater type and the phase of granule development.