| Bifidobacterium breve B2798（Bifidobacterium breve B2798,B.breve B2798）is sensitive to the culture environment,and there are problems such as low body density and difficult to maintain activity during production.The study found that temperature can lead to changes in the growth characteristics of the strain,which has a significant impact on its biomass and activity.In this experiment,bifidobacterium breve B2798 was used as the research object,the growth temperature of bifidobacterium breve was optimized by univariate static fermentation,and the biomass and activity of bacteria in the fermentation broth were verified by high-density culture experiments,which provided a basis for determining the end point of high-density fermentation,and a fermentation process was constructed to effectively improve the activity and biomass of bifidobacterium breve.The results of the study show that:（1）The experimental results showed that the biomass,viability and activity of Bifidobacterium breve B2798 at 37.0°C to 39.0°C were significantly higher than other culture temperatures（P<0.05）,indicating that the optimal culture temperature range of Bifidobacterium breve B2798 was 37.0°C to 39.0°C.（2）High-density fermentation analysis found that different culture temperatures also significantly affected the biomass,number of live bacteria and activity of Bifidobacterium breve B2798（P<0.05）.Based on the optimal fermentation temperature range screened out under static conditions,the optimal temperature of Bifidobacterium breve B2798 was further accurately adjusted by high-density fermentation through a fully automatic glass intelligent fermentation tank,and the results showed that the maximum number of live bacteria at the culture temperature of 38.0°C,up to（2.56±0.04）×1010CFU/m L,significantly higher than the number of live bacteria（1.94±0.01）×1010CFU/m L（P<0.01）at37.0°C.The number of live bacteria（2.45±0.02）×1010CFU/m L（P<0.01）at 39.0°C.The body density(OD600nm)was 7.59,which was significantly higher than 37.0°C,37.5°C,38.5°C and 39.0°C（P<0.05）.（3）The data analysis found that the high-density fermentation of Bifidobacterium breve B2798 was carried out under the condition of the optimal culture temperature of38°C,and the number of live bacteria was increased by 4.28 times compared with the static culture,the dry weight gain rate of the bacteria was 1.24 times higher than that of the static culture,and the wet weight yield of the bacteria was 1.93 times higher than that of the static culture.At the same time,it was further determined that the fermentation endpoint was at the end logarithmic stage of 14 hours in culture,and the number of live bacteria and the activity of fructose-6-phosphate phosphate were significantly higher than at other time points（P<0.05）.In summary,the optimal culture temperature of Bifidobacterium breve B2798 was38.0°C,and its fermentation endpoint should be controlled at the end of the logarithmic growth period of 14h in culture,at which time the number of live bacteria and activity of the strain were best maintained,which was easy to follow up related research and product development.This study explained the effects of different temperatures on the biomass,number of live bacteria and their activity of Bifidobacterium breve B2798,and provided basic data for the development of the late industrialization processing technology of this strain. |
