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Continuous dehydrogenation of a steroid with immobilized microbial cells: Effect of an exogenous electron acceptor
Author(s) -
Yang Ho Seung,
Studebaker Joel F.
Publication year - 1978
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.260200103
Subject(s) - dehydrogenation , electron acceptor , acceptor , chemistry , steroid , biochemistry , combinatorial chemistry , catalysis , physics , hormone , condensed matter physics
Whole cells of Pseudomonas testosteroni , induced to synthesize steroid‐transforming enzymes beforehand, have been immobilized by entrapment in polyacrylamide gel. The immobilized cells have then been used to catalyze the continuous Δ 1 ‐dehydrogenation of Reichstein's substance S under various conditions in the presence of phenazine methosulfate (PMS), an electron acceptor for the cell‐free Δ 1 ‐dehydrogenase. The presence of PMS substantially increases the rate of reaction when fed with the steroid substrate to a continuous stirred tank reactor containing the immobilized cells. The operational half‐life of the Δ 1 ‐dehydrogenase activity of the cells, about 103 hr under the best operating conditions, is essentially unaffected by the presence of PMS. Though the acceleration of the reaction may be due to PMS‐mediated passage of electrons from some component in the electron transport chain to molecular oxygen, the lack of a similar effect with methylene blue is consistent with the conclusion that PMS functions directly as the electron acceptor for the Δ 1 ‐dehydrogenase.