Background: Benefits of vitamin K have been reported by many studies recently, due to its
ability to reduce the risk of cardiovascular diseases and its potential benefits against osteoporosis. Specifically,
menaquinone-7 (MK-7), being the most potent form of vitamin K, has definitely received
most of the attention. Currently, solid or static liquid fermentation strategies are utilized for industrial
production of MK-7 by Bacillus strains. However, these strategies face fundamental operational and
scale-up issues as well as intense pellicle and biofilm formations which is problematic in static liquid
fermentation, due to heat and mass transfer inefficiencies they create.
Objective: The purpose of this study was to demonstrate that biofilm reactors will overcome the issues
associated with suspended cell reactors when using Bacillus strains to produce MK-7. The expectation
is that the use of biofilm reactors will result in a significant increase in the production of MK-7.
Method: Vitamin K production by Bacillus subtilis natto when grown in a biofilm reactor was evaluated
at various concentrations of the three major nutrients, glucose, yeast extract and casein. The data
was analyzed using response surface methodology (RSM).
Results: The maximum concentration of MK-7 in the biofilm reactors was 20.5±0.5 mg/L, which was
a 344 % increase when compared to the amount produced in suspended-cell reactors containing the
same optimum media composition.
Conclusion: These results demonstrate the potential of utilizing biofilm reactors for MK-7 production
on an industrial scale.