嗜热链球菌937增殖培养基及发酵条件的优化

Optimization of Enrichment Culture Medium and Fermentation Conditions for Streptococcus thermophilus 937

摘要:

该研究以化学限定培养基为基础，通过单因素实验、响应面实验和正交优化实验对嗜热链球菌937的培养基、培养条件进行优化。通过实验确定嗜热链球菌937最适培养基：乳糖20 g/L，酶解脱脂乳16.60%，大豆低聚肽18.88 g/L，乳清蛋白粉1.69%，10 mmol/L组氨酸、10 mmol/L异亮氨酸、5 mmol/L酪氨酸、1 mmol/L半胱氨酸和1 mmol/L谷氨酸、2 mg/L烟酸、0.5 g/L抗坏血酸、40 mg/L氯化镁、2 mg/L泛酸钙、4 mg/L盐酸硫胺素、0.4 g/L氯化钙。初始pH值6.5，接种量2%，39 ℃发酵，嗜热链球菌937活菌数高达1.75×109 CFU/mL。由此可见，该研究实现嗜热链球菌937低成本、高效率的培养技术，为高活菌数的嗜热链球菌商业产品的开发生产奠定基础。

Abstract:

The optimization process for Streptococcus thermophilus 937 involved starting from a chemically defined medium, followed by single-factor experiments, response surface experiments, and orthogonal optimization experiments to refine the culture medium and growth conditions. The experimentally determined optimal culture medium for Streptococcus thermophilus 937 is 20 g/L lactose, 16.60% enzymatic skim milk, 18.88 g/L soybean oligopeptide, 1.69% whey protein powder, 10 mmol/L histidine, 10 mmol/L isoleucine, 5 mmol/L tyrosine, 1 mmol/L cysteine, 1 mmol/L glutamic acid, 2 mg/L nicotinic acid, 0.5 g/L ascorbic acid, 40 mg/L magnesium chloride, 2 mg/L calcium pantothenate, 4 mg/L thiamine hydrochloride, and 0.4 g/L calcium chloride. The viable cell density of Streptococcus thermophilus 937 reached 1.75×109 CFU/mL when the initial pH was 6.5, with a 2% inoculum and a fermentation temperature of 39 ℃. This work achieved low-cost, highefficiency culture methods for Streptococcus thermophilus 937, and these findings lay a foundation for the development and production of commercial products via Streptococcus thermophilus cultures with high viable cell counts.