Isolation of Wild Yeasts from Freshwaters and Soils in Nonsan Stream and Sapgyoho in Chungcheongnam-do, Korea, and Microbiological Characteristics of the Unrecorded Wild Yeasts

Ji-Eun  Jang1   Seon-Jeong  Park1   Jeong-Su Moon1   Hyang Burm Lee2   Jong-Soo Lee1,*   

1Faculty of Biomedicine and Biotechnology, Paichai University, Daejeon 35345, South Korea
2Department of Agricultural Biological Chemistry, Chonnam National University Gwangju 61186, South Korea


This study aimed to isolate wild yeasts from water and soil sample of the Nonsan stream and Sapgyoho (lake) in Chungcheonnam-do, Korea, and to further characterize previously unrecorded wild yeast strains. In total, 102 strains, representing 55 different species of wild yeast were isolated from 95 samples collected from the Jangseoncheon and Ipchoncheon of Nonsan stream in Jellabuk-do and Chungcheonnam-do. Among these, 33 strains were isolated from alkalophilic yeast extract-peptone-dextrose (YPD) medium (pH 9.0), and 9 strains were isolated concurrently on general YPD medium (pH 6.5) and alkalophilic medium. Seventeen strains of Cryptococcus laurentii were predominantly isolated. Additionally, 65 strains, representing 27 different species of wild yeast were isolated from 58 samples obtained from Sapgyoho (lake). Among the 82 isolated wild yeast strains, 8 strains, including Candida fructus JSC 72-1(JSL-GGU 015), had not previously been recorded. All 8 previously unrecorded yeasts were oval in shape except C. fructus JSC72-1(JSL-GGU-015), and only the Filobasidium chernovii JSC39-1(JSL-GGU-013) strain formed spores. All strains except Pseudosydowia eucalypti JSC23-6(JSL-GGU-012) grew well in yeast extract-peptone-dextrose (YPD) and yeast extract-malt extract media and grew in vitamin-free medium. Four strains, including P.eucalypti JSC23-6(JSL-GGU-012) grew well in 15% NaCl-containing YPD medium. F.chernovii JSC39-1(JSL-GGU-013) and Sirobasidium intermedium JSC7-3(JSL-GGU-014) assimilated lactose, and five strains, including F. chernovii JSC39-1(JSL-GGU-013) also assimilated starch. All strains were resistant to 800 ppm of Ca, Cu, Li, and Mg ions.

Figures & Tables

Fig. 1-A. Phylogenetic tree of the unrecorded yeasts isolated from freshwaters and soils of Nonsan upstream, based on the nucleotide sequences of large subunit 26Sribosomal DNA D1/D2 region. The tree was generated by the neighbor-joining method, using MEGA 7. The bar indicates the number of substitutions per position. The new isolates from the present study are shown in bold and its detailed characteristics were described in Tables 3 and 4. (Bold type font; unrecorded yeasts.)