Optimization of cultural conditions of Beauveria bassiana pathogenic for ticks

Abstract:

The aim of this study was to establish and optimize standard laboratory techniques for cultivation and fermentation of a strain of Beauveria bassiana (B. bassiana AT17), which has shown potential biological activity against ticks. This will provide practical and experimental supports for the further research on preparation of biocontrol agents. Condition optimization was conducted by single factor experiment. The factors studied were basic culture medium, temperature, pH, carbon sources, nitrogen sources, microelements and liquid fermentation medium. The results showed that B. bassiana AT17 could grow well on PDA, PPDA, PDAY, SDAY and SMAY medium. Comparatively, B. bassiana AT17 had the fastest growth on PDA and the highest spore yields on PDAY. Temperature was the major factor that affects on growth speed and yields of B. bassiana AT17. It showed that 25 °C was the optimal temperature for both hyphal growth and the sporulation. B. bassiana AT17 could grow at pH 4?10 with the fastest growth in alkali condition, and produce optimal sporulation at pH 5?6. Based on all of fungal indexes, glucose and yeast were the best carbon and nitrogen sources. The best solid fermentation medium was wheat bran+indian meal+rice flour mixed with 3/4 SDAY containing suitable K+ in proportion of 2:1.