Title Electrochemical Reduction of Xylose to Xylitol by Whole Cells or Crude Enzyme of Candida peltata
Author Sun Mi Park, Byung In Sang1, Dae Won Park2, and Doo Hyun Park*
Address Department of Biological Engineering, Seokyeong University, Seoul 136-704, Republic of Korea, 1Division of Water Environment and Remediation, KIST, Hawolgok-dong, Sungbuk-gu, Seoul 136-791, Republic of Korea, 2Department of Energy and Environmental Engineering, Seoul National University of Technology, Seoul 139-743, Republic of Korea
Bibliography Journal of Microbiology, 43(5),451-455, 2005,
DOI
Key Words electrochemical oxidoreduction, graphite-Mn(IV) electrode, neutral red, xylitol, xylose reductase
Abstract In this study, whole cells and a crude enzyme of Candida peltata were applied to an electrochemical bioreactor, in order to induce an increment of the reduction of xylose to xylitol. Neutral red was utilized as an electron mediator in the whole cell reactor, and a graphite-Mn(IV) electrode was used as a catalyst in the enzyme reactor in order to induce the electrochemical reduction of NAD+ to NADH. The efficiency with which xylose was converted to xylitol in the electrochemical bioreactor was five times higher than that in the conventional bioreactor, when whole cells were employed as a biocatalyst. Meanwhile, the xylose to xylitol reduction efficiency in the enzyme reactor using the graphite-Mn (IV) electrode and NAD+ was twice as high as that observed in the conventional bioreactor which utilized NADH as a reducing power. In order to use the graphite-Mn(IV) electrode as a catalyst for the reduction of NAD+ to NADH, a bioelectrocatalyst was engineered, namely, oxidoreductase (e.g. xylose reductase). NAD+ can function in this biotransformation procedure without any electron mediator or a second oxidoreductase for NAD+/NADH recycling
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