ABSTRACT
Two piezophilic bacterial isolates belong to the Moritella group, Moritella japonica DSK1 and Moritella yayanosii DB21MT-5 (Table 2.1, Fig. 2.3). Strain DSK1 is moderately piezophilic and was isolated from the Japan Trench sediment at 6,356 m (Kato et al. 1995a). This is the first piezophilic and psychrophilic species identified in the genus Moritella (Nogi et al. 1998c). Its optimal growth conditions are 10°C and 10-50 MPa (Kato et al. 1995a, Nogi et al. 1998c). Strain DB21MT-5 was isolated from sediment of the Mariana Trench at 11,000 m (Kato et al. 1998). Its optimal growth pressure was 80 MPa and no growth was observed at pressure less than 50 MPa. A facultative piezophilic strain of the genus Moritella, designated PE36, was isolated from the North Pacific Ocean at 3,586 m (Yayanos, 1986). All these strains produce DHA, one of the characteristic properties of this genus (DeLong et al. 1997, Kato et al. 1998, Nogi et al. 1998c, Fang et al. 2003).
