           

2011A1702         BL14B2ࣂࢡࢸࣜ࢔㛵㐃≀㉁࠾ࡼࡧ DNA 㛵㐃≀㉁࡟ࡼࡿࣞ࢔࢔࣮ࢫࡢ
ศ㞳ᅇ཰ἲࡢᵓ⠏࡟ྥࡅࡓࣞ࢔࢔࣮ࢫࡢ྾╔࣓࢝ࢽࢬ࣒ࡢゎ᫂A Study on the Mechanism of Adsorption of Rare Earth Elements 㻔REE㻕 toEstablish Recovery Method of REE by Bacteria-related and DNA-relatedMaterials㧗ᶫ ჆ኵ a, ᐑᆅ ளἋ⨾ a, ⏣୰ ୓ஓ b, ᶓᒣ ⏤ె a
Yoshio Takahashia, Asami Miyajia, Kazuya Tanakab, Yuka Yokoyamaaabᗈᓥ኱Ꮫ኱Ꮫ㝔⌮Ꮫ◊✲⛉ᆅ⌫ᝨᫍࢩࢫࢸ࣒Ꮫᑓᨷ,ᗈᓥ኱Ꮫࢧࢫࢸࢼࣈࣝࢹ࢕࣋ࣟࢵࣉ࣓ࣥࢺ◊✲ࢭࣥࢱ࣮a Department of Earth and Planetary Systems Sciece, Graduate School of Science, Hiroshima University,bSustainable Development Research Center, Hiroshima University ࣞ࢔࢔࣮ࢫ㸦REE㸧ࢆศ㞳࣭ᅇ཰ࡍࡿࡓࡵࡢ᪉ἲ࡜ࡋ࡚ࠊᢸయ࡜ࡋ࡚ࣂࢡࢸࣜ࢔ࡸࣂࢡࢸࣜ࢔㛵㐃≀㉁㸦ⓑᏊ࡞࡝㸧ࢆ⏝࠸ࡓᡭἲࢆ㛤Ⓨࡋࠊࡑࡢ᪉ἲࡢ࣓࢝ࢽࢬ࣒ࢆゎ᫂ࡋࠊᡭἲࡢ᭱㐺໬ࢆ⾜࠺ࡓࡵ࡟ࠊࡇࢀࡽᢸయ࡟྾╔ࡉࢀࡓ REE ࢆ X ⥺྾཰ᚤ⣽ᵓ㐀ἲ㸦EXAFS ἲ㸧࡟ࡼࡾ᫂ࡽ࠿࡟
ࡋࡓࠋREE ࣃࢱ࣮ࣥ࠿ࡽࠊࡇࢀࡽᢸయࡀ REE ࡢศ㞳ᅇ཰࡟᭷ຠ࡛࠶ࡾࠊREE ࡢ⤖ྜࢧ࢖ࢺ࡜ࡋ࡚ࣜࣥ㓟ᇶࡀ㔜せ࡛࠶ࡿࡇ࡜ࡀ EXAFS ἲ࠿ࡽ᫂ࡽ࠿࡟࡞ࡗࡓࠋ࣮࣮࢟࣡ࢻ㸸 ࣞ࢔࢔࣮ࢫࠊࣂࢡࢸࣜ࢔ࠊ྾╔ࠊEXAFS⫼ᬒ࡜◊✲┠ⓗ㸸ࣞ࢔࢔࣮ࢫ㸦ᕼᅵ㢮ඖ⣲㸹REE㸧ࡣࠊࣛࣥࢱࣀ࢖ࢻ 15 ඖ⣲࡜ Sc࣭Y ࢆྵࡴඖ⣲⩌ࡢ⥲⛠࡛࠶ࡿࠋREE ࢆᵓᡂࡍࡿྛඖ⣲ࡣࠊࣁ࢖ࢸࢡ⏘ᴗ࡟࠾࠸࡚ᵝࠎ࡟฼⏝ࡉࢀ⌧௦♫఍ࢆᨭ࠼࡚࠸ࡿࡀࠊୡ⏺
ࡢ REE ㈨※ࡣṤ࡝ࡀ୰ᅜ࠿ࡽࡢ౪⤥࡟౫Ꮡࡋ࡚࠸ࡿࡓࡵࠊ᪂ࡓ࡞ REE ㈨※ࡢ㛤Ⓨ࡜ࣜࢧ࢖ࢡࣝᢏ⾡ࡢ☜❧ࡀᮃࡲࢀ࡚࠸ࡿࠋ≉࡟ REE ࡢ┦஫ศ㞳ᢏ⾡ࡣࠊ஫࠸࡟ᴟࡵ࡚㢮ఝࡢᣲືࢆ♧ࡍ REEࢆಶู࡟ศ㞳ࡋࠊ⏝㏵࡟ᛂࡌ࡚ࡑࢀࡒࢀࡢඖ⣲ࢆ฼⏝ࡍࡿࡓࡵ࡟ᚲ㡲࡞ࣉࣟࢭࢫ࡛࠶ࡿࠋᡃࠎࡣࠊ
ࣂࢡࢸࣜ࢔⣽⬊⾲㠃ࡀ REE ࢆ㧗⃰ᗘ࡟྾╔ࡍࡿ≉ᛶࢆᣢࡘ࡜ඹ࡟ࠊ≉࡟㔜 REE㻔TmࠊYbࠊLu㻕ࢆ㑅ᢥⓗ࡟⃰⦰ࡍࡿࡇ࡜ࢆぢฟࡋࠊࡑࡢ࣓࢝ࢽࢬ࣒ࢆ EXAFS ἲ࡟ࡼࡾ᫂ࡽ࠿࡟ࡋ࡚ࡁࡓ[1]ࠋࡇࢀࡲ࡛ࡢ◊✲࡛ࠊࣂࢡࢸࣜ࢔࡬ࡢ REE ࡢ⃰⦰ࡣࠊ⣽⬊ቨ࡟ྵࡲࢀࡿࣜࣥ㓟࡜ࡢ⤖ྜ࡟ࡼࡿࡇ࡜ࡀศ࠿ࡗ࡚࠸ࡿࠋ୍᪉࡛ࠊࣂࢡࢸࣜ࢔ࡣ౑⏝ࡍࡿ๓࡟ᇵ㣴ࡀᚲせ࡛࠶ࡾࠊࡲࡓẚ㍑ⓗศゎࡋࡸࡍࡃࠊᇵ㣴ࡋࡓྠࡌࣂࢡࢸࣜ࢔ࢆ⧞㏉ࡋ฼⏝ࡍࡿࡇ࡜ࡣᅔ㞴࡛࠶ࡿࠋࡑࡢࡓࡵࠊ㛵㐃≀㉁ࢆ฼⏝ࡋࡓࡼࡾࡼ࠸᪉ἲࡢ㛤Ⓨࡀᮃࡲࢀ࡚࠸ࡿࠋᡃࠎࡣࣜࣥ㓟࢚ࢫࢸࣝᇶࡀ REE ࡢ⃰⦰࡟㛵୚ࡍࡿࡇ࡜࠿ࡽࠊࡸࡣࡾࣜࣥ㓟࢚ࢫࢸࣝᇶࢆᣢࡘ DNA ࡸࡑࡢ㛵㐃≀㉁ࠊࡲࡓࣂࢡࢸࣜ࢔⣽⬊ቨࡢᶍᨃ≀㉁࡞࡝࡟╔┠ࡋࠊࡼࡾࡼ࠸ REE ࡢศ㞳ᅇ཰ᢏ⾡ࢆ᥈⣴ࡋ࡚࠸ࡿࠋࡑࡢ୰࡛ࠊDNAࠊDNA ࢆ㇏ᐩ࡟ྵࡴⓑᏊ㸦ࢧࢣࡢⓑᏊ㸧ࠊࣂࢡࢸࣜ࢔⣽⬊ቨ࡜㢮ఝࡢᵓ㐀ࢆᣢࡘࣜࣥ㓟ࢭ࣮ࣝࣟࢫ㸦ྜᡂရ㸧࡟╔┠ࡋࠊࡇࢀࡽࡢ≀㉁ࡢ REE ࡢศ㞳⃰⦰ᶵᵓࡢゎ᫂ࡢࡓࡵ࡟ࠊEXAFS ἲࢆ฼⏝ࡋࡓᐇ㦂ࢆ⾜ࡗࡓࠋᐇ㦂㸸ࡇࢀࡽࡢ≀㉁࡟ᑐࡍࡿ REE ࡢ྾╔ࡣࠊࡇࢀࡲ࡛ሗ࿌ࡋࡓࣂࢡࢸࣜ࢔࡟㢮ఝࡢ྾╔ᣲືࢆ♧ࡍࡇ࡜ࡀศ࠿ࡗࡓ㻔ᅗ㸯㻕[2]ࠋࡑ
ࡢ୰࡛ࡶࠊࣜࣥ㓟ࢭ࣮ࣝࣟࢫࡣࡼࡾ REEࢆ⃰⦰ࡍࡿ୍᪉ࠊREE ࡢ┦஫ศ㞳࡛ࡣⓑᏊࡀ᭱ࡶ᭷ຠ࡛࠶ࡿࡇ࡜ࡀ♧၀ࡉࢀࡓࠋࡇ࠺ࡋࡓ⃰⦰࣭┦஫ศ㞳ࡢ࣓࢝ࢽࢬ࣒ࢆゎ᫂ࡍࡿࡓࡵ࡟ࠊEXAFS ἲ࡛ᚓࡽࢀࡓ REE ࡢ⤖ྜࢧ࢖ࢺࢆ᥎ᐃࡋࡓࠋ௒ᅇࡣ୺࡟ࣜࣥ㓟ࢭ࣮ࣝࣟࢫ࡜ⓑᏊ࡟྾╔ࡉࢀࡓ LaࠊDyࠊ
Lu ࡟ࡘ࠸࡚ࠊBL14B2 ࡛ EXAFS ࡢᐃࢆ⾜ࡗࡓࠋLa ࡟ࡘ࠸࡚ࡣࠊLIII ྾཰➃࡛ࡣከ㟁Ꮚບ㉳ࡢᙳ㡪ࡀ኱ࡁ࠸ࡓࡵࠊK ྾཰➃࡛ࡢᐃࢆ⾜ࡗࡓࠋDy ࡜ Lu ࡟ࡘ࠸࡚ࡣࠊLIII ྾཰➃࡛ᐇ㦂ࢆ⾜ࡗࡓࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸⤖ᯝࡢ౛࡜ࡋ࡚ᅗ㸰࡟ pH3 ࡛ⓑᏊ࡟྾╔ࡉࢀࡓ Lu ࡢ EXAFS ࡢືᚄᵓ㐀㛵ᩘ㻔RSF㻕ࢆ♧ࡋࡓࠋࡑࡢ⤖ᯝࠊR+ǼR =3.4 Å௜㏆࡟኱ࡁ࡞ࣆ࣮ࢡࡀぢࡽࢀࡓࠋFEFF ࡛ᚓࡓࣃ࣓࣮ࣛࢱࢆ⏝࠸ࡓࣇ࢕ࢵࢸ࢕ࣥࢢ࡟ࡼࡾࠊࡇࡢᩓ஘ࡣ➨஧㏆᥋ཎᏊ࡜ࡋ࡚
ࣜࣥࢆ௬ᐃࡍࡿࡇ࡜࡛ㄝ࡛᫂ࡁࡿࡇ࡜ࡀศ࠿ࡗࡓࠋᚓࡽࢀࡓ Lu-P ࡢཎᏊ㛫㊥㞳ࡣ
3.862 Å ࡛࠶ࡗࡓࠋྠᵝ࡟᭱㏆᥋ࡢ㓟⣲࡜ࡢ Lu-O ࡢ㊥㞳ࡣ 2.261 Å ࡛࠶ࡗࡓࠋࣜࣥࡢࣆ࣮ࢡࡀ᫂☜࡟ぢࡽࢀࡓࡇ࡜ࡣࠊࣂࢡࢸࣜ࢔࡟྾╔ࡉࢀࡓ Lu ࡢሙྜ࡜ྠᵝ࡛࠶ࡾࠊⓑᏊ࡟࠾ࡅࡿ㔜 REE ࡢ⃰㞟࡜㛵㐃ࡋ࡚࠸ࡿ࡜ࡳࡽࢀࡿࠋࡓࡔࡋࠊࣜࣥ㓟ࡶྵࡵࡓ㓄఩Ꮚ࡜ࡢᖹᆒⓗ࡞⤖ྜ㊥㞳ࢆ཯ᫎࡍࡿ࡜ࡳࡽࢀࡿ Lu-O ࡣࠊࣂࢡࢸࣜ࢔ࡢሙྜ㻔Lu-O: ⣙ 2.20 Å㻕࡟ẚ࡭࡚ࡸࡸ㛗ࡃ࡞ࡗࡓࠋࡲࡓࣜࣥ࡜ࡢ㊥㞳ࡶࣂࢡࢸࣜ࢔ࡢሙྜ㻔Lu-P: ⣙ 3.80 Å㻕ࡼࡾࡶ㛗ࡃ࡞ࡗࡓࠋࡇࢀࡽࡣࠊࣜࣥ㓟௨እ࡟⤖ྜࢧ࢖ࢺࡀࣂࢡࢸࣜ࢔ࡢሙྜࡼࡾࡶከ࠸ࡇ࡜ࢆ♧၀ࡋ࡚࠾ࡾࠊࣂࢡࢸࣜ࢔࡟ẚ࡭࡚㔜REE ࡢ⃰㞟ࡀ༑ศ࡛࡞࠸ࡇ࡜㻔ᅗ㸯㻕࡜ᩚྜⓗ࡛࠶ࡿࠋpH 4 ࡛ⓑᏊ࡟྾╔ࡉࢀࡓ Lu ࡟ࡘ࠸࡚ࡣࠊࣜࣥࡢࣆ࣮ࢡࡣྠᵝ࡟☜ㄆࡉࢀࡓ㻔Lu-P: 3.899 Å㻕ࡀࠊ㓟⣲࡜ࡢ㊥㞳ࡣࡸࡸ㛗ࡃ࡞ࡾ 2.300 Å ࡜࡞ࡗࡓࠋࡲࡓ R+ǼR =2.7 Å ࡟ Lu-C ࡟⏤᮶ࡍࡿࣆ࣮ࢡࡀࡳࡽࢀࡓࠋࣂࢡࢸࣜ࢔࡛ࡣ pH ࡢቑຍ࡜ඹ࡟࢝ࣝ࣎࢟ࢩࣝᇶ࡜ࡢ⤖ྜࡀቑຍࡍࡿࡇ࡜ࡀ♧၀ࡉࢀ࡚࠾ࡾࠊྠᵝࡢഴྥࡀぢࡽࢀࡓࠋࡇࡢഴྥࡣࠊpH ࡢቑຍ࡜ඹ࡟㔜 REE ࡢ⃰㞟ࡢ⛬ᗘࡀపࡃ࡞ࡿࡇ࡜࡜ᩚྜⓗ࡛࠶ࡿࠋྠᵝ࡟ࣜࣥ㓟ࢭ࣮ࣝࣟࢫ࡛ࡶࠊpH 3.5 ࡟࠾࠸࡚ࠊLu-O ࡢ㊥㞳ࡀ 2.281 Å ࡛ࠊLu-P ࡢ㊥㞳ࡀ 3.806
Å ࡜࡞ࡗࡓࠋࣜࣥ㓟ࢭ࣮ࣝࣟࢫ࡛ࡶࣂࢡࢸࣜ࢔࡜ྠᵝ࡟㔜 REE ࡢ⃰㞟ࡀぢࡽࢀ࡚࠾ࡾࠊࡇࢀࡣࣜࣥ㓟ᇶ࡜ࡢ⤖ྜࡢᐤ୚࡟ࡼࡿ࡜ࡳࡽࢀࡿࠋ
ࡲࡓࠊREE ࡢᅇ཰⋡ࡸศ㞳ຠ⋡࡞࡝ࡢᐇ㦂࡟࠾࠸࡚ࡣࠊ≉࡟ DNA ࡸⓑᏊࢆ࣒࢝ࣛἲ࡛฼⏝ࡍࡿሙྜࠊỈ 100%ࢆ⁐㞳ᾮ࡜ࡍࡿ࡜ࠊᢸయࡢ␯Ỉᛶࡀᙉࡃ⁐፹ࡀ࠺ࡲࡃὶࢀ࡞࠸ࡇ࡜ࡀศ࠿ࡗ࡚࠸
ࡿࠋࡑࡢࡓࡵࠊ࢚ࢱࣀ࣮ࣝࢆᩘ 10%⛬ᗘΰྜࡋࡓ⁐፹ࢆ⏝࠸࡚࠾ࡾࠊࡑࡢࡼ࠺࡞ሙྜ࡟ࠊREE ࡢ⤖ྜࢧ࢖ࢺࡀ࡝ࡢࡼ࠺࡟ኚ໬ࡍࡿ࠿ࡶ EXAFS ࠿ࡽㄪ࡭ࡓࠋࡑࡢ⤖ᯝࠊ࢚ࢱࣀ࣮ࣝࡢ᭷↓࡟ࡼࡗ࡚ⓑᏊࡸࣜࣥ㓟ࢭ࣮ࣝࣟࢫ࡬ࡢᒁᡤᵓ㐀࡟኱ࡁ࡞ኚ໬ࡀぢࡽࢀ࡞࠸ࡇ࡜ࡶศ࠿ࡗࡓࠋ௒ᚋࡢㄢ㢟㸸ᮏ◊✲࡛ㄪ࡭ࡓᢸయࢆ࣒࢝ࣛἲ࡟⏝࠸ࡿࡓࡵ࡟ࡣࠊࡇࢀࡽᢸయࢆ඘ሸࡋࡓ࣒࡛࢝ࣛỈࡀࡘࡲࡿࡇ࡜࡞ࡃὶࢀࡿࡇ࡜ࡀᚲせ࡛࠶ࡿࡀࠊⓑᏊࢆ⏝࠸ࡓሙྜࠊ࢚ࢱࣀ࣮ࣝࢆῧຍࡋ࡚ࡶὶฟ㏿ᗘࡀࡸࡸ㐜ࡃ࡞ࡿࡇ࡜ࡀศ࠿ࡗࡓࠋࡑࡢࡓࡵࠊREE ࡢ㏿ࡸ࠿࡞ὶฟࢆຓࡅࡿࡓࡵࠊࡼࡾぶỈᛶࡢ≀㉁࡟
DNA ࡞࡝ࢆ⤖ྜࡉࡏࡓ≀㉁ࡢ㛤Ⓨࡀ௒ᚋᮃࡲࢀࡿ[3]ࠋཧ⪃ᩥ⊩㸸[1] Y. Takahashi, M. Yamamoto, Y. Yamamoto, and K. Tanaka, Geochim. Cosmochim. Acta 74, 5443
㻔2010㻕.
[2] Y. Takahashi, T. Hirata, T. Ozaki, H. Shimizu, and D. Fortin, Chem. Geol. 244, 569 㻔2007㻕.
[3] 㧗ᶫ჆ኵࠊ㏆⸨࿴༤ࠊBio Industry 14, 42 㻔2011㻕.