Capsanthin Production in by Overexpression of Capsanthin/Capsorubin Synthase from .

Capsanthin, a characteristic red carotenoid found in the fruits of red pepper (), is widely consumed as a food and a functional coloring additive. An enzyme catalyzing capsanthin synthesis was identified as capsanthin/capsorubin synthase (CCS) in the 1990s, but no microbial production of capsanthin has been reported. We report here the first successful attempt to biosynthesize capsanthin in by carotenoid-pathway engineering. Our initial attempt to coexpress eight enzyme genes required for capsanthin biosynthesis did not detect the desired product. The dual activity of CCS as a lycopene β-cyclase as well as a capsanthin/capsorubin synthase likely complicated the task. We demonstrated that a particularly high expression level of the gene and the minimization of byproducts by regulating the seven upstream carotenogenic genes were crucial for capsanthin formation in . Our results provide a platform for further study of CCS activity and capsanthin production in microorganisms.