Fig. 2.

Light-induced carotenoid production in T. thermophilus. (A) Colonies of the wild-type (WT) strain, the litR mutant (ΔlitR), and the CRP/FNR family transcriptional regulator gene mutant (ΔTTP55), each harboring the plasmids pTEV (empty vector; control), pTEV-55 (pTEV carrying TTP55), and pTEV-litR (pTEV carrying litR). (B) Colonies of the mutant lacking Cbl biosynthesis genes (Δcob) grown in the absence (−MeCbl) and presence (+MeCbl) of 0.1 mM MeCbl. All colonies were developed under light (L) and dark (D) conditions at 60°C for 2 days on solid TM medium.