Antioxidative enzymes and substances involve in the activity of improving the oxidative tolerance of Pichia caribbica by ascorbic acid

The purpose of this research was to investigate the mechanisms involved in improving oxidative tolerance of Pichia caribbica by using ascorbic acid (VC). VC is noted for its ability to enhance oxidative tolerance. Therefore, this study investigated the effects of VC on the cellular oxidative damage as well as antioxidative enzymes activities of P. caribbica under oxidative stress. The results indicated that oxidative damage occurred in P. caribbica especially under the non-VC treatment condition. The application of VC significantly reduced the oxidative damage. On the other hand, system scavenging the excess reactive oxidative species such as antioxidative enzymes and substances was initiated when exposed to the H2O2. Moreover, VC enhanced the efficacy of antioxidative enzymes (ascorbic peroxidase, peroxidase, polyphenol oxidase) and antioxidative substances (glutathione and trehalose). Thus, VC improved the oxidative tolerance of P. caribbica, which could lead to an enhancement of biocontrol activity of P. caribbica.