Carotenoids are a group of tetraterpene
pigments widely used in
the food, pharmaceutical, and cosmetic industries. Torulene, torularhodin,
and β-carotene, three principal carotenoids synthesized by Rhodotorula glutinis ZHK, possess strong health-promoting
properties such as antioxidant, provitamin A, and antitumor. Here,
the effect of different salt conditions on carotenoids production
of R. glutinisZHK was investigated.
The results showed that the total carotenoids were significantly enhanced
in 0.5 M (3.91 mg/L) and 0.75 M (5.41 mg/L) NaCl treatments than that
in 1.0 M (0.35 mg/L) and control (1.42 mg/L) after 120 h of cultivation.
Of which, the increase in torulene and torularhodin production acts
as the main contributor to the enhancement of total carotenoids. Transcriptome
profiling revealed that salt stress efficiently promotes the gene
expression of crtI, which could explain the molecular
mechanisms of the enhanced torulene and torularhodin production under
salt stress. Further experiments indicated that torulene and torularhodin
play an important role in quenching excrescent reactive oxygen species
induced by salt stress. Together, the present study reports an effective
strategy for simultaneously improving torulene and torularhodin production
in R. glutinis ZHK.