Development and testing of selective media for mucoralean fungi

Three selective media, each containing agar, 20 ppm benomyl, 200 ppm choram phenicol, mineral salts, NH4CI, yeast extract and respectively starch, sucr ose or acetic acid, were tested to support growth of 133 mucoralean fungal strains, representing 65 species. The three media supported growth of strai ns of species belonging to Absidia, Actinomucor, Backusella, Mortierella su bgenus Micromucor, Mucor, Rhizopus and Thamnostylum. Most representatives o f Mortierella subgenus Mortierella did not grow on the media. The ability o f the media to select mucoralean fungi among fungal populations in two diff erent soil samples was subsequently determined using the soil plate techniq ue. This was accomplished by comparing the fungal taxa and numbers obtained on the three media to those observed on a relatively non-selective medium. The latter (MYPps) contained agar, malt extract, peptone, yeast extract, p enicillin and streptomycin sulphate. When using this medium to determine th e presence of mucoralean fungi in soil from Dry Sandy Highveld Grassland, o nly the genera Mortierella and Mucor were detected. When the three selectiv e media were inoculated with the soil, however, members of Absidia, Cunning hamella, Gongronella and Rhizopus were also found. Absidia and Mortierella were found when soil from Cold Highveld Grassland was used as inoculum for the MYPps medium. The use of the selective isolation media revealed also th e presence of Mucor. This study showed that by using selective isolation me dia in combination with: a relatively non-selective medium, more mucoralean taxa could be isolated from a particular soil sample than when only the no n-selective medium was used.