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Regeneration of NADH in a bioreactor using yeast cells immobilized in alginate fiber: I. Method and effect of reactor variables
Author(s) -
Stevenson E.,
Ibbotson P. G.,
Spedding P. L.
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260420107
Subject(s) - calcium alginate , bioreactor , alcohol dehydrogenase , nad+ kinase , chemistry , fiber , dehydrogenase , immobilized enzyme , ethanol , chromatography , enzyme , yeast , saccharomyces cerevisiae , biochemistry , calcium , organic chemistry
Abstract Saccharomyces cerevisiae cells immobilized in a calcium alginate fiber reactor were used as a source of alcohol dehydrogenase for the NAD + ‐to‐NADH reaction. The reaction was catalyzed by enzyme in cells on the surface of the fiber. Internal diffusional effects were present. The enzyme cell concentration was optimized by harvesting cells finally grown under anaerobic conditions. The results were expressed as an apparent reaction rate constant that was independent of NAD + and excess ethanol concentration, was slightly affected by flow rate above a minimum value, and increased with immobilized cell concentration in the fiber. The reaction was complete after 6 to 7 h under optimal conditions of 36°C and 9.5 pH. The latter was 0.5 pH units above the free enzyme optimum, indicating that microenvironmental effects were in evidence. © 1993 John Wiley & Sons, Inc.