Optimization of the Culture Medium of <i>Beauveria bassiana</i> and Spore Yield Using Response Surface Methodology

Abstract

Beauveria bassiana has distinct nutrient requirements depending on the growth stage, with the mycelial growth stage being particularly nutrient-intense. When nutrients are exhausted, B. bassiana produces numerous spores that re-germinate and release visible hyphae under suitable environmental conditions. This study aimed to use low-cost agricultural by-products for developing an optimized sporulation medium. Single-factor experiments revealed that potato, wheat bran, and wheat had the greatest influence on sporulation after 14 d of culture. Wheat, wheat bran, and corncob had the strongest effect on spore production. Using a mathematical model and Box–Behnken design, the maximum predicted sporulation using the stock medium was 5.55 × 106/mL. The optimized formula comprised 54.82 g potato, 77.74 g wheat bran, and 101.48 g wheat. The actual stock medium produced a spore yield of 5.52 × 106/mL. Similarly, the maximum predicted sporulation was 15.66 × 106/mL for the culture medium. The optimized formula comprised 50.81 g wheat, 99.6 g wheat bran, and 112.59 g corncob, with a spore yield of 15.69 × 106/mL. The high consistency between predicted and experimental values indicated that our model can accurately determine the effect of medium on sporulation.

Keywords

• <i>Beauveria bassiana</i>
• hazelnut
• hazel weevil
• sporulation