title: Optimisation and comparison of liquid and dry formulations of the biocontrol yeast Pichia anomala J121.
abstract: The biocontrol yeast Pichia anomala J121 can effectively reduce mould growth on moist cereal grains during airtight storage. Practical use of microorganisms requires formulated products that meet a number of criteria. In this study we compared different formulations of P. anomala. The best way to formulate P. anomala was freeze-drying. The initial viability was as high as 80%, with trehalose previously added to the yeast. Freeze-dried products could be stored at temperatures as high as 30 degrees C for a year, with only a minor decrease in viability. Vacuum-drying also resulted in products with high storage potential, but the products were not as easily rehydrated as freeze-dried samples. Upon desiccating the cells using fluidised-bed drying or as liquid formulations, a storage temperature of 10 degrees C was required to maintain viability. Dependent on the type of formulation, harvesting of cells at different nutritional stresses affected the initial viabilities, e.g. the initial viability for fluidised-bed-dried cells was higher when the culture was fed with excess glucose, but for freeze-drying it was superior when cells were harvested after depletion of carbon. Using micro-silos we found that the biocontrol activity remained intact after drying, storage and rehydration for all formulations.
authors.affiliation: Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7027, SE-750 07, Uppsala, Sweden. petter.melin@mikrob.slu.se
authors.forename: Petter
authors.initials: P
authors.lastname: Melin
authors.forename: Sebastian
authors.initials: S
authors.lastname: Håkansson
authors.forename: Johan
authors.initials: J
authors.lastname: Schnürer
mesh_terms: D003451:Cryoprotective Agents; D005612:Freeze Drying; D050296:Microbial Viability; D010572:Pest Control, Biological / Q000379:methods*; D010843:Pichia / Q000502:physiology*; D011309:Preservation, Biological; D013696:Temperature; D013997:Time Factors; D014199:Trehalose
chemical_list: D003451:Cryoprotective Agents; D014199:Trehalose