Biotechnology Letters

, Volume 23, Issue 20, pp 1723–1727

Immobilization of yeast alcohol dehydrogenase on magnetic nanoparticles for improving its stability


DOI: 10.1023/A:1012485221802

Cite this article as:
Liao, MH. & Chen, DH. Biotechnology Letters (2001) 23: 1723. doi:10.1023/A:1012485221802


Yeast alcohol dehydrogenase (YADH) was immobilized covalently on Fe3O4 magnetic nanoparticles (10.6 nm) via carbodiimide activation. The immobilization process did not affect the size and structure of magnetic nanoparticles. The YADH-immobilized magnetic nanoparticles were superparamagnetic with a saturation magnetization of 61 emu g−1, only slightly lower than that of the naked ones (63 emu g−1). Compared to the free enzyme, the immobilized YADH retained 62% activity and showed a 10-fold increased stability and a 2.7-fold increased activity at pH 5. For the reduction of 2-butanone by immobilized YADH, the activation energies within 25–45 °C, the maximum specific activity, and the Michaelis constants for NADH and 2-butanone were 27 J mol−1, 0.23 mol min−1 mg−1, 0.62 mM, and 0.43 M, respectively. These results indicated a structural change of YADH with a decrease in affinity for NADH and 2-butanone after immobilization compared to the free enzyme.

immobilizationmagnetic nanoparticlesstabilityyeast alcohol dehydrogenase

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  1. 1.Department of Chemical EngineeringNational Cheng Kung UniversityTainan, TaiwanRepublic of China