Effect of light on beta-carotene accumulation in Blakeslea trispora.

Abstract

SUMMARY: Cultures of a plus and a minus strain of Blakeslea trispora, grown either separately or together in light, accumulated only 40% of the β-carotene of corresponding cultures grown in darkness. The trisporic acids which accumulated in culture media of plus and minus strains grown together in light differed in their extinction spectra from the trisporic acids in the medium of cultures grown in darkness. Exposure of a trisporic acid extract from dark-grown cultures to light altered its extinction spectrum and decreased its carotenogenic activity. Only the ultraviolet portion of the spectrum of the lamps employed brought about this change in the extinction spectrum of the trisporic acid extract. The visible portion of the spectrum, however, was able to depress β-carotene accumulation in cultures without bringing about a change in the extinction spectrum of the trisporic acids produced. It seems likely that the formation of trisporic acids with altered extinction spectra is not responsible for the decrease in the accumulation of β-carotene.