Study on Lacticaseibacillus casei TCS fermentation kinetic models and high-density culture strategy

Area of Science:

• Microbiology
• Biotechnology
• Food Science

Background:

• Lacticaseibacillus casei TCS is crucial for fermented dairy products due to its aromatic properties.
• High-density cultivation of L. casei TCS aims to boost production yields and overcome fermentation limitations.
• Challenges include acid inhibition, salt stress, and substrate limitation, hindering efficient industrial-scale production.

Purpose of the Study:

• To optimize medium composition and fermentation conditions for high-density culture of Lacticaseibacillus casei TCS.
• To develop a cost-effective and robust strategy for industrial probiotic production.
• To enhance the production efficiency and yield of L. casei TCS for aroma starter applications.

Main Methods:

• Employed single-factor, orthogonal experimental designs, and response surface methodology for medium optimization.
• Utilized artificial neural network (ANN) and genetic algorithm (GA) optimization for enhanced bacterial counts.
• Applied logistic growth and Luedeking-Piret models for fermentation kinetics, coupled with ion exchange (Amberlite IRA 67) and fed-batch fermentation.

Main Results:

• Optimal medium composition and fermentation conditions significantly increased viable bacterial count.
• ANN-GA optimization method led to a substantial increase in bacterial density.
• Maximum cell density reached 10.01 lg CFU/mL, a 9.3-fold increase, by alleviating acid inhibition and stress factors.

Conclusions:

• Developed a robust and cost-effective strategy for industrial L. casei TCS production.
• Successfully optimized probiotic production processes, overcoming key fermentation challenges.
• The study provides a foundation for high-yield aroma starter production in dairy and functional food industries.