Horiike Takumi, Otsuka Osamu, Tanaka Yasuhiro, Terahara Takeshi, Imada Chiaki, Yamashita Mitsuo
Rare Metal Bioresearch Center, Research Organization for Advanced Engineering, Shibaura Institute of Technology.
Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology.
J Gen Appl Microbiol. 2019 Dec 19;65(5):246-253. doi: 10.2323/jgam.2018.11.003. Epub 2019 Mar 29.
Tellurium (Te) has been increasingly used as a semiconductor material in copious amounts, with a concomitant increase in its discharge from industrial effluents and mining wastewater into the environment. However, soluble Te, such as tellurate (VI) and tellurite (IV), is toxic to organisms. Thus, highly efficient technologies need to be developed for a double-benefit detoxification and recovery of soluble Te from industrial and mining wastewater. Since industrial wastewater contains high concentrations of salt, salt-tolerant microorganisms that metabolize rare metals such as Te have been the subject of focus for the effective detoxification and recovery of Te. In the present study, a total of 52 salt-tolerant tellurate-reducing microorganisms were isolated from marine environmental samples. Of these, 18 strains achieved greater than, or equal to, 50% removal of water-soluble Te from a medium containing 0.4 mM tellurate after 72 h incubation. The 18 isolated strains belonged to 13 species of the following 9 genera: Sulfitobacter, Ruegeria, Hoeflea, Alteromonas, Marinobacter, Pseudoalteromonas, Shewanella, Idiomarina, and Vibrio. No microorganism has been reported to reduce tellurate and tellurite from six of the aforementioned genera, namely, Sulfitobacter, Ruegeria, Alteromonas, Marinobacter, Idiomarina, and Vibrio. Especially, one of the isolates Sulfitobacter sp. strain TK39B, removed 82% (w/w) of soluble Te with a 4% NaCl tolerance. These results showed that salt-tolerant tellurate-reducing bacteria that can be used in the detoxification and recovery of Te are widely present in the marine environment.
碲（Te）作为一种半导体材料的使用量日益增加，与此同时，其从工业废水和采矿废水中排放到环境中的量也随之增加。然而，可溶性碲，如碲酸盐（VI）和亚碲酸盐（IV），对生物体有毒。因此，需要开发高效技术，以实现从工业和采矿废水中对可溶性碲进行双重效益的解毒和回收。由于工业废水含有高浓度盐分，能够代谢碲等稀有金属的耐盐微生物已成为有效解毒和回收碲的研究重点。在本研究中，共从海洋环境样本中分离出52株耐盐碲酸盐还原微生物。其中，18株菌株在72小时培养后，从含有0.4 mM碲酸盐的培养基中去除了大于或等于50%的水溶性碲。分离出的18株菌株属于以下9个属的13个物种：硫杆菌属、鲁杰氏菌属、霍夫勒氏菌属、交替单胞菌属、海杆菌属、假交替单胞菌属、希瓦氏菌属、嗜盐碱杆菌属和弧菌属。上述9个属中的6个属，即硫杆菌属、鲁杰氏菌属、交替单胞菌属、海杆菌属、嗜盐碱杆菌属和弧菌属，此前尚未有微生物能还原碲酸盐和亚碲酸盐的报道。特别是，其中一株分离菌株硫杆菌属菌株TK39B，在4% NaCl耐受性下，去除了82%（w/w）的可溶性碲。这些结果表明，可用于碲解毒和回收的耐盐碲酸盐还原细菌广泛存在于海洋环境中。
