Production of sterols in modified yeast
AssigneeDsm IP Assets B.V.
InventorsHans-Peter Hohmann, Regina Leber, Martin Lehmann, Corinna Odar, Barbara Petschacher, Harald Pichler, Birgit Ploier
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Abstract
The present invention is related to production of a sterol mix in a modified yeast cell, wherein the amount of zymosterol present in said mix is dramatically reduced or abolished via modification of sterol acyltransferase activity within said yeast. The modified yeast cell can be used for production of vitamin D3 or derivatives and/or metabolites thereof.
Claims6
A process for the production of a sterol mix in a yeast cell, said sterol mix comprising 7-dehydrocholesterol (7-DHC) and zymosterol, and said process comprising cultivating said yeast cell under conditions suitable for sterol production, wherein
- (a) the gene encoding the endogenous C22 sterol desaturase (ERG5) and the gene encoding the endogenous Delta(24)-sterol C-methyltransferase (ERG6) have been inactivated in the yeast cell,
- (b) the yeast cell comprises a mutation in the gene encoding Acyl-CoA:sterol acyltransferase 2 (ARE2) that reduces the activity of endogenous ARE2,
- (c) the yeast cell expresses a heterologous enzyme selected from EC 1.3.1.72 having sterol Δ24-reductase activity on lathosterol, zymosterol or trienol, wherein the enzyme EC 1.3.1.72 having sterol Δ24-reductase activity is originated from plant or vertebrate,
- (d) the amount of zymosterol present in the sterol mix is 3% or less based on the total amount of sterols, and
- (e) the percentage of 7-DHC within said sterol mix is at least 87% based on total amounts of sterol in said mix.
Dependencies are inferred from the claim text.