| Project/Area Number |
62470113
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
発酵工学
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| Research Institution | Hiroshima University |
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Principal Investigator |
NAGAI Shiro FAC. OF ENGINEERING, HIROSHIMA UNIV., PROFESSOR, 工学部, 教授 (70013307)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIO Naomichi FAC. OF ENGINEERING, HIROSHIMA UNIV., ASSOC. PROFESSOR, 工学部, 助教授 (30034383)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1989: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1988: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1987: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Sulfonated Polysul-Fone Membrane / NADP(H) Retention / NADPH Regeneration / Xylitol Production / Methanogens / Hydrogenase / Immobilized Cells / Photo-Crosslinkable Resin Prepolymer / NADH再生系 / Methanosarcina barkeri / シスチン / システイン / 水素による生化学的還元 / 荷電膜バイオリアクター / メタン生成細菌 / ヒドロゲナーゼ / スルホン化ポリエーテルスルホン膜 / キシリトール生産 / システイン生産 / NADP(H)保持反応器 / NADP(H)再生系 |
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| Research Abstract |
Successful application of coenzyme-dependent enzymes requires simultaneous use of the required coenzymes(free or immobilized) with coenzymes regenerating system. Hence, in this report, a novel method for in situ regeneration and retention of native NADP(H) for the enzymatic conversion of xylose to xylitol with hydrogen was attempted in an ionized membrane reactor.
The enzymatic production of xylitol from xylose using NADPH-dependent xylose reductase of Candida pelliculosa coupling with the oxidoreductase system of Methanobacterium Sp. capable of recycling NADP(H) was carried out. In this reaction, H_2 is the substrate for reducing F_<420> via hydrogenase and then the reduced F_<420> is coupled with F_<420>-NADP oxidoreductase to reduce exogenous NADP^+ to NADPH. The results obtained were as follows.
1. A sulfonated polysulfone membrane reactor was used for in situ retention of NADP(H). The membrane could almost completely reject the permeation of NADP(H)(92 and 97%), F_<420>(97%) and the required enzymes(100%), but not reject for the permeation of xylitol(product). After 4-h reaction for the production of xylitol from xylose(93% yield), the membrane could reject the permeation of the remaining NADP(H) and F_<420> at the level of 90 and 95%, respectively.
2. The enzymatic conversion of xylose into xylitol by the immobilized cells of C. pelliculosa coupled with the immobilized cells of Methanobacterium sp. was done using H_2 as an electron donor for regenerating NADPH. Benzene treatment of the co-immobilized cells with a photo-crosslinkable resin prepolymer, ENT 4000, increased the permeability of NADP(H) into the cells. Besides, treatments with glutaraldehyde and hexamethylenediamine to the immobilized cells were done to enhance the stability of immobilized-cell activity. Thus, the continuous production of xylitol in a column reactor packed with the co-immobilized cells could operate stably for 2 weeks.
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