title: Production of microsclerotia by Brazilian strains of Metarhizium spp. using submerged liquid culture fermentation.
abstract: We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium anisopliae (Ma), M. acridum (Mc) and M. robertsii (Mr). These fungi were grown in a liquid medium containing 16 g carbon l⁻¹ with a carbon:nitrogen ratio of 50:1. One hundred milliliters cultures were grown in 250 ml Erlenmeyer flasks in a rotary incubator shaker at 28 °C and 200 rpm for 5 days. Five-day-old MS were harvested, mixed with diatomaceous earth (DE) and air-dried for 2 days at 30 °C. The air-dried MS-DE granular preparations were milled by mortar + pestle and stored in centrifuged tubes at either 26 or -20 °C. Desiccation tolerance and conidia production were assessed for dried MS granules by measuring hyphal germination after incubation for 2 days on water agar plates at 26 °C and for conidia production following 7 days incubation. Yields of MS by all strains of Metarhizium were 6.1-7.3 × 10⁶ l⁻¹ after 3 days growth with maximum MS yields (0.7-1.1 × 10⁷ l⁻¹) after 5 days growth. No differences in biomass accumulation were observed after 3 days growth, whereas Ma-CG168 showed the highest biomass accumulation after 5 days growth. Dried MS-DE preparations of all fungal strains were equally tolerant to desiccation (≥93 % germination) and the highest conidia production was obtained by MS granules of Mc-CG423 (4 × 10⁹ conidia g⁻¹). All MS granules showed similar stability after storage at either 26 or -20 °C for 3.5 months.
authors.affiliation: Embrapa Rice and Beans, Rodovia GO-462, Km 12, Zona Rural, C.P. 179, Santo Antônio de Goiás, GO, 75375-000, Brazil, gabriel.mascarin@embrapa.br.
authors.forename: Gabriel Moura
authors.initials: GM
authors.lastname: Mascarin
authors.forename: Nilce Naomi
authors.initials: NN
authors.lastname: Kobori
authors.forename: Rayan Carlos
authors.initials: RC
authors.lastname: de Jesus Vital
authors.forename: Mark Alan
authors.initials: MA
authors.lastname: Jackson
authors.forename: Eliane Dias
authors.initials: ED
authors.lastname: Quintela
mesh_terms: D018533:Biomass; D001938:Brazil; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism*; D003890:Desiccation; D005285:Fermentation; D025301:Hyphae / Q000254:growth & development; D052981:Metarhizium / Q000145:classification / Q000254:growth & development*
chemical_list: D003470:Culture Media; D002244:Carbon