Production of <i>Bacillus thuringiensis</i> in “On Farm” Biofactories Is So Efficient Like a Commercial Product to Control <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae)
2024
Ítalo Alves Freire | Izabela Nunes do Nascimento | Gabriela Teodoro Rocha | Pedro de Luca Buffon dos Santos | Breno Béda dos Reis Cunha | Antônia Débora Camila de Lima Ferreira | Flávia Melo Moreira | Marcelo Tavares de Castro | Rose Gomes Monnerat
The biological control of pests and diseases in Brazilian crops has increased substantially, and the large-scale multiplication of microorganisms, a practice known as “On Farm”, is now being used by farmers. In this study, we aimed to produce and evaluate the quality of <i>Bacillus thuringiensis</i> var. <i>kurstaki</i> strain HD-1 in “On Farm” biofactories under three aeration rates (0.2, 0.5 and 0.8 air volume/volume of medium/min) (vvm), with regard to the production of endospores and crystals, contaminants, and to calculate the lethal concentration 50 (LC<sub>50</sub>) against <i>Spodoptera frugiperda</i> larvae. After 48 h, the number of viable spores differed significantly between 0.2 (5.75 × 10<sup>7</sup>), 0.5 (1.33 × 10<sup>8</sup>) and 0.8 (5.40 × 10<sup>8</sup>) vvm. The culture media did not show enough selectivity. A significant difference was observed for the LC<sub>50</sub> calculated for 0.2 vvm (7.06 × 10<sup>4</sup>), 0.5 vvm (2.07 × 10<sup>4</sup>), 0.8 vvm (4.40 × 10<sup>3</sup>), and the commercial product (3.79 × 10<sup>3</sup>). The results of this study showed that the aeration rate affects the multiplication efficiency of <i>B. thuringiensis</i> in biofactories. In addition, post-process quality control analyses found no pathogenic contamination, reinforcing the safety and viability of the production process. The 0.8 vvm rate resulted in the greater production of spores and crystals, and statistically similar results to the commercial product for the control of <i>S. frugiperda</i>.
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