Establishment of Technology for Microbial Accumulation of Rare Earth Elements.

建立了稀土富集菌的筛选体系。分离出能在al/100稀释营养琼脂上生长的寡营养细菌。将每种分离物在含有钇（Y，5 ppm）的稀释营养肉汤中培养。通过筛选，获得了7株（A-G）菌株，其中B和D菌株经鉴定为食酸丛毛单胞菌，F菌株为奇异食菌。稀土元素的富集光谱在这些孤立体中各不相同。稀土元素的富集方式有两种模式。一种是从La到Nd富集的细菌，另一种是除上述元素外还富集Tb、Dy、Ho和Er的细菌。共获得5株放线菌，其中3株为放线菌。菌株3-1对Yb有富集作用，这些分离菌株适用于稀土元素的富集、分离和提纯。

We established the screening system for rare earth elements accumulating bacteria. Oligotrophic bacteria which are able to grow on al/100 diluted nutrient agar were isolated. Each isolant was cultured in yttrium (Y,5 ppm) containing diluted nutrient broth. We obtained 7 strains (A-G) which could decrease Y below 2.5ppm.Strains B and D were identified as Comamonas acidovorans, and strain F was Variovorax paradoxus. The spectra of rare earth element accumulation were diferent each other among these isolants. There are two patterns on the mode of rare earth element accumulation. The one is the bacteria which accumulate from La to Nd, and the other is the bacteria which accumulate Tb, Dy, Ho and Er in addition of the above elements.Next, we screened Yb accumulating bacteria, which was used as a representative of heavy rare earths. We obtained 5 strains, in which 3 strains were actinomycetes. Strain 3-1 accumulated Yb specifically.These isolants are applicable to accumulation, separation and purification of rare earth elements.