|Kim, Beom Soo|
Submitted to: New Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2010
Publication Date: 4/15/2010
Citation: Kim, B., Kim, H., Hou, C.T. 2010. Effect of surfactant on production of oxygenated unsaturated fatty acids by Bacillus megaterium ALA2. New Biotechnology. 27(1):33-37. Interpretive Summary: The United States has a large amount of surplus soybean oil annually, and using vegetable oils or their component fatty acids as starting material provides a new opportunity for bioindustry. Previously, we discovered that a microbial strain ALA2 produced 12,13,17-trihydroxy-9(Z)-octadecenoic acid (12,13,17-THOA) from a fatty acid components of soybean oil. 12,13,17-THOA has anti-plant pathogenic fungi activities. We have been trying to scale-up production of 12,13,17-THOA for evaluation in industrial application. In this paper, we found that in the presence of surfactant Tween 80, the production can be increased about 6-fold. Success of our studies in scale-up production of this new product will benefit polymer industries, specialty chemical companies, biomedical companies and the U.S. agricultural community.
Technical Abstract: Bacillus megaterium ALA2 NRRL B-21660 was well studied to produce many oxygenated unsaturated fatty acids from linoleic acid. Its major product, 12,13,17-trihydroxy-9(Z)-octadecenoic acid (12,13,17-THOA) inhibited the growth of many plant pathogenic fungi . We were not able to demonstrate 12,13,17-THOA production in a fermentor. Now, we investigated the effect of surfactants on the production of 12,13,17-THOA. Surfactant type (SO-25, Tween-80 and Triton X-100) at various concentrations were evaluated on their effects on cell growth and production of 12,13,17-THOA. Among these surfactants tested, Triton X-100 decreased cell growth and 12,13,17-THOA production while Tween-80 with 1.0% increased 12,13,17-THOA production by more than 2 times over control. The addition of Tween-80 but without linoleic acid did not produce 12,13,17-THOA, suggesting that Tween-80 was not a substrate for the production of 12,13,17-THOA. When the concentration of substrate was changed with a fixed concentration of Tween-80 (1.0%), maximum 12,13,17-THOA production was achieved at 250 mg substrate per 50 ml. In a pH and dissolved oxygen controlled fermentor and with 1.0% Tween-80, both 12,13,17-THOA production and productivity increased to 553 mg/L and 24.0 mg/L/h, respectively. Then, we conducted THOA production in a fermentor without control of pH and DO, but with aeration through medium surface not from Spurger, and with various amounts of Tween-80 to compare with the results obtained in flask runs. Both additions with 0.1% and 0.5% Tween-80 and the control runs produced poor amounts of product 12,13,17-THOA. The maximum 12,13,17-THOA production was observed at 1.0% Tween-80 at a yield of 650 mg/L. Thus the production of 12,13,17-THOA in fermentor was successfully demonstrated.