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Published May 1994 | metadata_only
Journal Article

Intracellular expression of Vitreoscilla hemoglobin alters the aerobic metabolism of Saccharomyces cerevisiae


Vitreoscilla hemoglobin (VHb) has been expressed in Saccharomyces cerevisiae, and its influence on yeast aerobic metabolism has been investigated. New expression vectors were constructed to express VHb constitutively under the control of the ADH‐1 promoter. The presence of VHb was shown by Western blot analysis. VHb has been shown to localize predominantly in the cytoplasm. Batch fermentation results indicated that the wild‐type strain expressing VHb exhibited a shift in the carbon flux toward ethanol production, with no significant alteration in the specific growth rate. This effect was not observed if cells were grown under respiration inhibition, indicating that the metabolic effect of VHb is likely linked to respiration. Expression of VHb in the adh° strain MC65‐2A, which produces ethanol only via a respiration‐coupled pathway, revealed that ethanol production was decreased and cells reached a higher final cell density in a culture of the VHb‐expressing strain. Growth enhancement due to expression of VHb was observed only during the final stage of culture growth when the acetaldehyde produced during the first growth phase was used as a substrate. This metabolic effect of intracellular VHb was seen more clearly in an acetaldehyde fed‐batch fermentation in which VHb‐expressing cells grew to at least 3‐fold higher final cell density. These results suggest that the action of VHb is likely linked to electron transfer.

Additional Information

© 1994 American Chemical Society and American Institute of Chemical Engineers. Accepted November 4, 1993. This work was supported by the Advanced Industrial Concepts Division of the U.S. Department of Energy. W.C. was supported in part by a Predoctoral Training Grant in Biotechnology from the National Institute of General Medical Sciences (National Research Service Award 5 T32 GM 08346-04, Pharmacology Science Program). We thank Dr. M. Ciriacy and Dr. G. Bitter for providing the adh° strain MC65-2A and the plasmid pYE, respectively. We appreciate the assistance of J. DeModena and S. Magnolo.

Additional details

August 20, 2023
August 20, 2023