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Title: Antimicrobial potential of bioconverted products of omega-3 fatty acids by Pseudomonas aeruginosa PR3

item Hou, Ching

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/21/2008
Publication Date: 11/21/2008
Citation: Kang, S., Bajpai, V.K., Yoon, J., Kim, H., Hou, C.T. 2008. Antimicrobial potential of bioconverted products of omega-3 fatty acids by Pseudomonas aeruginosa PR3 [abstract]. Symposium on Biocatalysis and Biotechnology. O-4, p. 81.

Interpretive Summary:

Technical Abstract: Bioconverted omega-3 fatty acids, eicosapentaenoic acid (bEPA) and docosahexanoic acid (bDHA), obtained from the microbial conversion of non-bioconverted eicosapentaenoic and docosahexaenoic acids by Pseudomonas aeruginosa PR3 were evaluated for their antimicrobial potential. bEPA and bDHA at 5 µl/ml exhibited 34 to 60 and 55 to 65% fungal mycelium growth inhibition, respectively, against Rhizoctonia solani, Botrytis cinerea, Fusarium oxysporum, Fusarium solani, Sclerotinia sclerotiorum, Phytophthora capsici and Colletotrichum capsici along with their respective minimum inhibitory concentrations ranging from 250 to 500 and 125 to 500 µg/ml. Also bEPA and bDHA had a strong detrimental effect on spore germination of all the tested plant pathogens as a percentage of spore germination inhibition ranging from 60 to 100%. Concerning the in vitro susceptibilities of bEPA and bDHA, further in vivo studies were carried out on selected plant pathogenic fungi such as C. capsici, P. capsici, F. solani and F. oxysporum. bEPA and bDHA at the initial concentration of 3000 and 1500 µg/ml, respectively, revealed 100% antifungal effect against leaf spot of pepper (C. capsici), leaf scorch of pepper (P. capsici) and wilt/necrosis of tomato (F. oxysporum). However, further dilutions of bEPA and bDHA applied to the plants had moderate antifungal effect in vivo. bEPA and bDHA also exhibited potential antibacterial effects against food spoilage and food-borne pathogenic bacteria as a diameter of zones of inhibitions (7 to 12 and 7-14 mm) as well as minimum inhibitory concentrations (350 to 5000 and 250 to 4800 µg/ml), cell viable count and scanning electron microscopic assay. Further, elaborative column chromatographic study conducted on bEPA resulted in the isolation of a single bioconverted compound from bEPA, designated as MS1. The structure of the compound was elucidated as eicosahexaenoic acid on the basis of spectral analysis (MS, H-1NMR and 13NMR). MS1 also displayed promising antifungal effect against C. capsici and F. solani with MIC value of 30 µg/ml, for each fungal strain. The results of this study demonstrate that microbial bioconversion of unsaturated fatty acids may prove to be very valuable in generating potential antimicrobial agents to control fungal plant diseases as well as food spoilage and food-borne pathogenic bacteria causing severe losses to agro- and food industries, respectively.