title: Improved shelf life of dried Beauveria bassiana blastospores using convective drying and active packaging processes.
abstract: The yeast form (blastospore) of the dimorphic insect-pathogenic fungus Beauveria bassiana can be rapidly produced using liquid fermentation methods but is generally unable to survive rapid dehydration processes or storage under non-refrigerated conditions. In this study, we evaluated the influence of two convective drying methods, various modified atmosphere packaging systems, and storage temperatures on the desiccation tolerance, storage stability, and virulence of blastospores of B. bassiana ESALQ 1432. All blastospore formulations were dried to <5 % water content equivalent to aw < 0.3. The viability of B. bassiana blastospores after air drying and spray drying was greater than 80 %. Vacuum-packaged blastospores remained viable longer when stored at 4 °C compared with 28 °C with virtually no loss in viability over 9 months regardless the drying method. When both oxygen and moisture scavengers were added to sealed packages of dried blastospore formulations stored at 28 °C, viability was significantly prolonged for both air- and spray-dried blastospores. The addition of ascorbic acid during spray drying did not improve desiccation tolerance but enhanced cell stability (∼twofold higher half-life) when stored at 28 °C. After storage for 4 months at 28 °C, air-dried blastospores produced a lower LC80 and resulted in higher mortality to whitefly nymphs (Bemisia tabaci) when compared with spray-dried blastospores. These studies identified key storage conditions (low aw and oxygen availability) that improved blastospore storage stability at 28 °C and will facilitate the commercial development of blastospores-based bioinsecticides.
authors.affiliation: Embrapa Arroz e Feijão, Rodovia GO-462, km 12, Zona Rural, C. P. 179, Santo Antônio de Goiás, GO, 75375-000, Brazil. gabriel.mascarin@embrapa.br.|United States Department of Agriculture, Agriculture Research Service, Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, 1815 N. University St, Peoria, IL, 61604, USA. gabriel.mascarin@embrapa.br.|Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP, CEP 13418-900, Brazil. gabriel.mascarin@embrapa.br.
authors.forename: Gabriel Moura
authors.initials: GM
authors.lastname: Mascarin
authors.affiliation: United States Department of Agriculture, Agriculture Research Service, Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, 1815 N. University St, Peoria, IL, 61604, USA. mark.jackson@ars.usda.gov.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jackson
authors.affiliation: United States Department of Agriculture, Agriculture Research Service, Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, 1815 N. University St, Peoria, IL, 61604, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Behle
authors.affiliation: United States Department of Agriculture, Agriculture Research Service, Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, 1815 N. University St, Peoria, IL, 61604, USA.
authors.forename: Nilce N
authors.initials: NN
authors.lastname: Kobori
authors.affiliation: Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP, CEP 13418-900, Brazil.
authors.forename: Ítalo Delalibera
authors.initials: ÍD
authors.lastname: Júnior
mesh_terms: D052982:Beauveria / Q000502:physiology*; D003681:Dehydration; D004355:Drug Stability; D004356:Drug Storage; D007306:Insecticides; D050296:Microbial Viability; D019064:Product Packaging; D013172:Spores, Fungal / Q000502:physiology*; D013696:Temperature
chemical_list: D007306:Insecticides
keywords: Air drying; Desiccants; Liquid fermentation; Mycoinsecticides; Oxygen scavengers; Spray drying; Storage stability