Efficient media for high menaquinone-7 production: response surface methodology approach.

Area of Science:

• Microbiology
• Biotechnology
• Nutritional Science

Background:

• Menaquinone-7 (MK-7) is a vital form of vitamin K2 with significant health implications.
• Optimizing fermentation processes is crucial for efficient and high-yield production of bioactive compounds like MK-7.

Purpose of the Study:

• To investigate the impact of various nutrients on menaquinone-7 production by Bacillus subtilis natto.
• To determine optimal fermentation conditions for maximizing menaquinone-7 yield.

Main Methods:

• Utilized design of experiments for nutrient screening and central composite face design for optimization.
• Fermented Bacillus subtilis natto at 40°C for six days, monitoring key parameters daily.
• Analyzed pH, bacterial growth, amino acid profiles, glycerol, and menaquinone-7 concentrations.

Main Results:

• Identified an optimal medium: 5% yeast extract, 18.9% soy peptone, 5% glycerol, and 0.06% K2HPO4.
• Achieved a maximum menaquinone-7 concentration of 62.32 ± 0.34 mg/L, the highest reported.
• Observed rapid MK-7 accumulation during the exponential growth phase, with nutrient depletion correlating with production.

Conclusions:

• The optimized fermentation strategy significantly enhances menaquinone-7 production.
• Nutrient composition plays a critical role in maximizing menaquinone-7 yield in Bacillus subtilis natto cultures.
• The study provides a validated model for predicting and achieving high menaquinone-7 concentrations.