Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/15/2004
Publication Date: 12/16/2004
Citation: Zhang, S., Schisler, D.A., Jackson, M.A., Boehm, M.J., Slininger, P.J. 2004. USDA-ARS, Ohio State University cooperative research on biological control of fusarium head blight 2: Cold temperature shock during production of Cryptococcus nodaensis OH 182.9 enhances cell survival after air-drying. National Fusarium Head Blight Forum Proceedings, December 11-15, 2004, Orlando, FL. p. 383-387.
Technical Abstract: Fresh biomass or frozen concentrates of Cryptococcus nodaensis OH 182.9 (NRRL Y-30216) significantly decreased Fusarium head blight in greenhouse and field trials. Fermentation, formulation, and drying studies are necessary and important in order to simplify transportation, storage, and application of this agent. Air-drying is a convenient and economical drying method for developing microbial products. In experiments designed to test the effect of temperature shock during liquid cultivation on cell survival after air-drying, OH 182.9 was grown at various temperatures in semidefined complete liquid media, with cells grown at 25ºC for 48 h serving as a control. Harvested cultures were mixed with 10% diatomaceous earth (DE), vacuum filtered, and air dried for 20 h at 60-70% RH. Cell survival at 4ºC for 36 weeks after air-drying was evaluated. In general, cells grown at 25ºC for 20 h and then cultivated at 15ºC for 28 h survived air-drying better than control cells. The survival of cells subjected to heat shock at 31ºC generally did not differ from control cells regardless of whether heat shock was applied at the late exponential or early stationary stage of growth. In another experiment designed to test the effect of cold temperatures on cell survival after air-drying, prolonged (28 h) cold shock at 10 and 15ºC after incubation at 25ºC for 20 h enhanced the stability of a DE-formulated OH 182.9 product. In greenhouse tests, air-dried OH 182.9 cell products stored at 4ºC maintained a higher biocontrol efficacy than those stored at 25ºC.