Comprehensive Comparisons of Five Kinds of Culture Media for Cultivating Fungal Spores at Different Viable States in Water

Abstract

At present, there is no unified culture medium to quantify the cultivability of fungal spores in water, making comparisons between studies difficult. This study intended to select an appropriate medium to obtain a lower percentage of viable but nonculturable Aspergillus spores at different viable states (freshly prepared, impaired-treated) and fungi in actual water. Five kinds of media ((dichloran rose bengal chloramphenicol (DRBC) agar, potato dextrose agar (PDA), dichloran 18% glycerol (DG-18) agar, rose bengal (RB) agar, and yeast extract dextrose chloramphenicol (YDC) agar) were selected. To obtain the result quickly and colony counting clearly for freshly prepared Aspergillus spores, the optimal incubation time was determined, and the cultivating effectiveness of media was: DRBC > RB > YDC > DG-18 > PDA. The DRBC medium exhibited better performance in quantifying impaired spores treated by ultraviolet or chlorine. Besides, RB medium was optimal for fungal enumeration in actual water. DRBC and RB media exhibited higher potential capacity in cultivating Aspergillus spores at different viable states because the existence of rose bengal restricted the size of the colony and the lower content of glucose limited the rapid growth of colonies. This study provides meaningful information for selecting a suitable medium to quantify fungal spores at different viable states.