Oxidative stress induced by plasma-activated water stimulates astaxanthin production in Phaffia rhodozyma

Astaxanthin is used extensively in the nutraceutical, aquaculture, and cosmetic industries. The current market necessitates higher astaxanthin production from Phaffia rhodozyma (P. rhodozyma) due to its higher cost compared to chemical synthesis. In this study, a bubble discharge reactor was developed to generate plasma-activated water (PAW) to produce PAW-made yeast malt (YM) medium. Due to oxidative stress induced by PAW, strains cultured in 15 and 30 min-treated PAW-made medium produced 7.9 ± 1.2 % and 12.6 ± 1.4 % more carotenoids with 15.5 ± 3.3 % and 22.1 ± 1.3 % more astaxanthin, respectively. Reactive oxygen species (ROS) assay results showed that ROS generated by plasma-water interactions elevated intracellular ROS levels. Proteomic analysis revealed increased expression of proteins involved in the cellular response to oxidative stress as well as carotenoid biosynthesis, both of which contribute to higher yields of astaxanthin. Overall, this study supports the potential of PAW to increase astaxanthin yields for industrial-scale production.