How to achieve a breakthrough in high-density fermentation of Bifidobacterium bifidum?
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.
