How to achieve a breakthrough in high-density fermentation of Bifidobacterium bifidum?
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- Issue Time
- Mar 25,2025
Summary
Bifidobacterium bifidum F35, as an important intestinal probiotic, has multiple functions such as relieving inflammation, regulating metabolism, and clearing free radicals. However, its industrial production has long been limited by harsh anaerobic conditions and low viable bacterial concentrations.
In traditional MRS medium, the viable cell count of F35 is only 1.4 × 10 ⁸ CFU/mL, and the nitrogen source utilization rate is low and the fermentation cycle is long, making it difficult to meet the requirements for large-scale production.
How to increase production? The Jiangnan University team has built an efficient high-density fermentation system
Firstly, optimize the L-cysteine golden ratio by adding 1.5g/L L-cysteine hydrochloride, significantly improving the anaerobic environment and increasing bacterial survival rate by 300%.
At the same time, intelligent and precise pH regulation is achieved, with a constant pH of 5.7 in a 200L fermentation tank and a glucose utilization rate of up to 99%, breaking through the inhibition of bacterial growth caused by pH fluctuations in traditional processes.
Using a dual nitrogen source combination and a combination of yeast peptone 10g/L and yeast extract FM98510g/L, the utilization rate of amino acid nitrogen increased by 2.2 times and the number of viable bacteria increased by 3 times.
Accurately regulate the carbon nitrogen ratio, achieve a golden ratio of 1.6:1 by adding 32g/L glucose, and maximize bacterial biomass.
The experimental results are exciting!
At a pilot scale of 200L, the optimized culture medium resulted in a viable cell count of F35 exceeding 8.01 × 10 ⁹ CFU/mL, which was 56 times higher than the initial MRS medium.
At the same time, the utilization rate of reducing sugars reached 99.06%, and the utilization rate of amino acid nitrogen increased to 35.82%, achieving efficient conversion of nutrients.
What are the prospects for the industrial application of this method?
One is to reduce the cost of nitrogen sources by 40%, improve the utilization rate of fermentation raw materials, and significantly enhance the feasibility of large-scale production.
At the same time, based on highly active freeze-dried bacterial powder, clean probiotic milk tablets can be developed to expand the market for dairy products and functional foods.
