Nghiên cứu tối ưu một số điều kiện sinh trưởng và sinh bào tử của chủng lợi khuẩn Bacillus subtilis-B23 sử dụng trong chăn nuôi gia cầm

Abstract

The study was conducted to optimize some growth and development conditions to achieve the maximum number of vegetative cells of the Bacillus subtilis-B23 strain. The colony titration technique was used to quantify CFU/mL. The results showed that at 1% seeding concentration, the largest number of B. subtilis-B23 cells will be achieved after 14 hours (9.25 ± 0.04 log CFU/mL). The temperature of 37°C was the most suitable for the growth of B. subtilis-B23 (9.45 ± 0.06 log CFU/mL). At a seeding rate of 1% and a cultivation temperature of 37°C, the optimal shaking speed was 80 rpm/min, achieving an average bacterial density of 9.61 ± 0.02 log CFU/mL. There is no obvious difference in the number of cells obtained when tested with 3 environments MT1, MT2, MT3; however, the results recorded in MT1 environment showed the highest number of bacterial cells (9.64 ± 0.079 log CFU/mL). The optimal number of spores formed after 2 hours of culture in LB medium supplemented with KCl and MgSO4. Therefore, optimizing the culture conditions for B. subtilis-B23 will result in the highest number of vegetative cells and the greatest yield of B. subtilis-B23 spores.