Isolation of halophilic and halotolerant bacteria from a Japanese salt field and comparison of the partial 16S rRNA gene sequence of an extremely halophilic isolate with those of other extreme halophiles

• Published in: Biodiversity and conservation 1994-10, Vol.3 (7), p.632-642
• Main Authors: Takashina, Tomonori, Otozati, Kiyotaka, Hamamoto, Tetsuo, Horikoshi, Koki
• Format: Article
• Language: English
• Subjects: Brackish
• ISSN: 0960-3115; 1572-9710
• DOI: 10.1007/BF00114206

Halophilic and halotolerant bacteria were isolated from soil samples of a Japanese salt field, an environment where salt concentrations vary annually from 1 g of each of the five samples collected, over 1 x 10 super(3) bacterial colonies (colony forming units (cfu)/g) grew on agar medium containing 2M Na super(+). In contrast, 0-4 bacterial colonies (cfu/g) were observed on agar medium containing 4M Na super(+). Two of the five samples contained numerous bacteria (10 super(2)-10 super(3) cfu/g) capable of growth on a 2M Na super(+) alkaline (pH = 9.5) medium, while few bacterial colonies were observed from the other three samples. Only one of the five samples was shown to contain bacteria capable of growth on a 4M Na super(+) alkaline medium. Most of the bacteria isolated on 4M Na super(+) agar were eubacteria, but one extreme halophile (TR-1, already described as Haloarcula japonica JCM7785) was also isolated. The 16S rRNA sequence of TR-1 was determined and shows high homology (94.4-98.5%) to H. marismortui and H. sinaiiensis. These results suggested that: 1) environments with seasonally varying salinity can harbour halotolerants as well as halopiles and, 2) closely related halophiles can be isolated from geographically distant habitats.