ARS | Publication request: Fluidized-Bed Drying and Storage Stability of Cryptococcus flavescens OH 182.9, a Biocontrol Agent of Fusarium Head Blight

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 17, 2009
Publication Date: February 16, 2010
Citation: Dunlap, C.A., Schisler, D.A. 2010. Fluidized-bed drying and storage stability of Cryptococcus flavescens OH 182.9, a biocontrol agent of Fusarium head blight. Biocontrol Science and Technology. 20(5):465-474.

Interpretive Summary: In this research, we developed a process to produce dried granules of an agriculturally important yeast. This yeast has previously been shown to be effective in controlling Fusarium head blight or scab in wheat. This technology will allow for large-scale production of yeast using common commercial equipment. The work describes how to produce moist granules of yeast, which can then be dried. The drying protocols for the granules is reported. The storage stability of the granules produced under different conditions was monitored for one year. The data is used to produce guidelines for selecting storage conditions for microorganisms. This research benefits scientists and manufacturers developing processes for dried microbial preparations. In addition, this research has the potential to directly benefit wheat and barley farmers, by reducing the development time of a scab control product.

Technical Abstract: A method to produce dried granules of Cryptococcus flavescens (formerly Cryptococcus nodaensis) OH 182.9 was developed and the granules evaluated for storage stability. Small spherical granules were produced and dried using a fluidized bed dryer. A drying and survival curve was produced for the process of fluidized bed drying at 30 C. The granules were dried to different moisture contents (4, 7, 9, and 12 percent) and evaluated for storage stability at 4 C for up to a year. The results show the storage stability varied significantly across this moisture content range. The 9 percent moisture content sample had the best short-term stability (up to 4 months), while 4 percent moisture content had the best long-term survival (1 year). A desorption isotherm of C. flavescens was determined and modeled. The results of the storage stability and drying studies are interpreted in context of the desorption isotherm.