Comparison of air-drying methods for evaluating the desiccation tolerance of liquid culture-produced blastospores of Paecilomyces fumosoroseus
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- Cliquet, S. & Jackson, M. World Journal of Microbiology and Biotechnology (1997) 13: 299. doi:10.1023/A:1018535124352
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Various drying methods were tested to identify a standard procedure for evaluating the desiccation tolerance of liquid culture-produced blastospores of Paecilomyces fumosoroseus. Since our work is focused on optimizing fermentation conditions for the production of P. fumosoroseus, the criteria for selecting a drying method included ease of use, moderate spore survival after drying and limited variation in spore survival. Three air-drying methods were tested: P. fumosoroseus blastospores mixed with silica gel, with sand, or with diatomaceous earth. Humidity controlled drying was used in the diatomaceous earth drying method. Blastospore survivals after drying were 19% (C.V. range, 32 to 45%), 82% (C.V. range, 26 to 43%), and 2% (C.V. range 32 to 50%) for the silica gel, sand, and diatomaceous earth methods, respectively. Blastospores dried using the silica gel and sand methods had been rinsed in 0.7 m polyethylene glycol before drying and rehydrated in the same solution for determination of survival. The variation observed within each method was similar. The silica gel drying method was selected as most appropriate for our studies based on moderate blastospore survival (19%) and ease of use.