The photoregulation of carotenoid biosynthesis inAspergillus giganteusmut.alba

✍ Scribed by Mohamed El-Jack; Alan Mackenzie; Peter M. Bramley

• Publisher: Springer-Verlag
• Year: 1988
• Tongue: English
• Weight: 805 KB
• Volume: 174
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00394874

✦ Synopsis

Aspergillus giganteus mut. alba grown in darkness produced no carotenoids, but illuminated shake cultures accumulated 170 pg. g-1 dry weight of fl-carotene. Maximum carotenoid production occurred in white light of energy fluence rate of 50 W. m-z. Blue light, but not red light, induced fl-carotene formation. A light induction period of 10 h was required for maximum fl-carotene synthesis, and this was attained 48 h after illumination. 5-Fluorouracil, actinomycin D and cycloheximide prevented photoinduction of carotenogenesis, indicating that photoregulation is at the transcriptional level. Comparisons of carotenogenic enzyme activities of light-and dark-grown cultures showed that phytoene synthetase, phytoene dehydrogenase and lycopene cyclase were totally photoinduced. Photoinduction of all three carotenogenic enzymes occurred after 12 h illumination. Squalene formation increased some four-fold upon illumination.