|Kuo, Tsung Min|
|Kim, H - FORMER ARS, POST-DOC|
Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 6, 2001
Publication Date: N/A
Interpretive Summary: Abundant vegetable oils represent attractive renewable resources for the production of useful chemicals. We are investigating microbial conversion of vegetable oils and their component fatty acids to value-added products. Previously, we found a new bioconversion reaction that produced a novel compound with chemical structure similar to a naturally occurring antifungal agent. In this study, we further defined the culture and reaction conditions to achieve a maximum yield of the bioconversion. Physiological tests confirmed the antifungal property of this new compound having the best activity known against the fungus that causes blast disease in rice plants. Successful industrial development of this biochemical will provide a means to control rice blast, the most important fungal disease affecting rice production worldwide. This research is a component of ARS National Program 306 -- New Uses of Plant Products.
Technical Abstract: The production and its potential use of a novel trihydroxy unsaturated fatty acid, 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD), were investigated. TOD was formed by Pseudomonas aeruginosa PR3 (NRRL B-18602) in a culture supplied with exogenous ricinoleic acid. The yield of TOD production was always higher in a rich culture medium than in minimal screening medium. Extending the conversion time from 48 to 72 h prior to lipid extraction led to a 65% reduction in yield, indicating that TOD was further metabolized by strain PR3 and that control of reaction time is important to achieving a maximum yield. The optimum culture density, reaction time, pH, temperature, and substrate concentration for the production of TOD were: 20-24 h culture growth, 48 h, 7.0, 25 deg C, and 1% (vol/vol), respectively. Under optimum conditions, the yield of TOD production was greater than 45%. TOD was found to be an antifungal agent most active against the fungus that causes blast disease in rice plants, the most important fungal disease affecting rice production worldwide.