Optimization Of Production Of Volatile Organic Compounds By Candida Intermedia C410and Evaluation Of Its Control Efficacy Against Postharvest Diseases Of Strawberry

This study optimized the condition for production of volatile organic compounds by Candida intermedia C410and evaluated its control efficacy against postharvest diseases of strawberry and gray mold disease on tomato. All results are summarized below:1. The factors of carbon source, nitrogen source, pH value and temperature that affect VOCs production of Candida intermedia C410in the medium were determined by using bioassay method. The results includes,1. when yeast reach the highest biomass in the the MCDA medium, the VOCs production can significantly inhibit the mycelial growth of B. cinerea;2. the most suitable carbon sources for the growth of yeast are glucose and maltose;3. the most suitable inorganic nitrogen sources for the growth of yeast is ammonium sulfate;4. the most suitable organic nitrogen for the growth of yeast is arginine;5. the most suitable pH range for yeast growth was5-7; and6. the optimum growth temperature was25℃.2. A total of177fungal isolates associated with postharvest diseases of strawberry were obtained. All the isolates were classified as10different genera of phytopathogenic fungi based on their cultural morphology and ITS sequences. By using double-dish set and fruit inoculation test, we confirmed that the volatile organic compounds produced by Candida intermedia C410can effectively control postharvest diseases of strawberry.3. The results from the two years (2011and2012) field experiment indicated that the Candida intermedia C410cells suspension had a significant control effect againest gray mold disease to greenhouse tomato.4. We screaned the flour and rice husk as best fermentation substrate of Candida intermedia C410and the optimal preparation process of the dry yeast. The most appropriate centrifugation conditions and washing liquid concentration are at5000r/min for20min and1%respectively. In addition, the best drying temperature and time are25℃and30min respectively. The Tween80:Span60(1:1) is determined to be the best emulsifier for protecting dry yeast cell without losing activity during the drying and rehydration process. Moreover, the screened fermentation substrate and the yeast spore suspension could produces VOCs with a a significant inhibitory effect for disease of strawberries during the storage process.