Commercial Production of Astaxanthin with Paracoccus carotinifaciens.

Paracoccus carotinifaciens is an aerobic Gram-negative bacterium that exhibits motility by a peritrichous flagellum. It produces a carotenoid mixture containing astaxanthin as the main component. Selective breeding of P. carotinifaciens has been performed using classical techniques for mutation induction, such as chemical treatment and ultraviolet irradiation, and not using genetic engineering technology. The commercial production of astaxanthin with P. carotinifaciens has been established by optimizing fermentation medium and conditions in the process. Dehydrated P. carotinifaciens is used as a coloring agent for farmed fish and egg yolks. Compared with the administration of chemically synthesized astaxanthin, dehydrated P. carotinifaciens imparts more natural coloration, which is favored by consumers. In addition, astaxanthin-rich carotenoid extracts (ARE) derived from P. carotinifaciens are developed for human nutrition. Animal and clinical studies with ARE for evaluating its efficacy have been conducted and suggested that ARE would be useful for preventing anxiety, stomach ulcer, and retinal damage, as well as improving cognitive function. The efficacy is anticipated to result from not only astaxanthin but also other carotenoids in ARE, such as adonirubin and adonixanthin, in some studies. Hence, astaxanthin commercially produced with P. carotinifaciens has been applied widely in animals and humans.