Submitted to: Mexican Congress of Microbiology
Publication Type: Proceedings
Publication Acceptance Date: April 10, 2002
Publication Date: N/A
Technical Abstract: Various media components and culture inocula were tested to improve P. fumosoroseus spore production rates, yield and stability. Conidia and liquid culture-produced spores of various strains of P. fumosoroseus were compared as inoculum. Inoculation of liquid media with blastospores at concentrations of at least 1 x 10(6) spores/mL resulted in the rapid production of higher concentrations of blastospores [ca. 1 x 10(9) spores/mL after 48 hours fermentation time) for all strains tested. The rapid germination rate of blastospores (90% after 6 hr incubation) compared to conidia (>90% after 16 hr incubation) and the use of higher inoculum rates reduced the fermentation time from 96 to 48 hr for maximal spore yields. Liquid media supplemented with acid hydrolyzed casein or yeast extract as nitrogen sources supported the production of high concentrations of blastospores that were significantly more desiccation-tolerant (79-82% survival after drying) when compared to blastospores produced in media supplemented with other nitrogen sources (50-12% survival after drying). For rapid spore production, requirements for trace metals and vitamin supplementation were dependent on the type of hydrolyzed casein used in the medium. Fermentor studies with two strains of P. fumosoroseus yielded high concentrations [1.3-1.8 x 10(9) spores/ml] of desiccation-tolerant blastospores in 48-hr fermentations. These studies have demonstrated that the infective spores of various strains of the fungal bioinsecticide Paecilomyces fumosoroseus can be rapidly produced using deep-tank, liquid culture fermentation techniques.