A carotenoid-producing yeast strain, isolated
from the sub-arctic, marine copepod Calanus finmarchicus,
was identified as Rhodosporidium babjevae
(Golubev) according to morphological and biochemical
characteristics and phylogenetic inference from the
small-subunit ribosomal RNA gene sequence. The total
carotenoids content varied with cultivation conditions in
the range 66–117 lg per g dry weight. The carotenoid
pool, here determined for the first time, was dominated
by torularhodin and torulene, which collectively constituted
75–91% of total carotenoids under various regimes
of growth. b-Carotene varied in the range 5–23%.
A high-peptone/low-yeast extract (weight ratio 38:1)
marine growth medium favoured the production of
torularhodin, the carotenoid at highest oxidation level,
with an average of 63% of total carotenoids. In standard
yeast medium (YM; ratio 1.7:1), torularhodin averaged
44%, with increased proportions of the carotenes,
torulene and b-carotene. The anticipated metabolic
precursor c-carotene (b,w-carotene) constituted a minor
fraction ( £ 8%) under all conditions of growth