Extraction of menaquinone-7 for supplementation of food

The addition of menaquinone-7 (MK-7) to the diet substantially reduces the risk of bone fractures and cardiovascular disorders, which are both major health issues globally. The concentration of MK-7 in food products is low and there is a need for supplementary MK-7. This vitamin can be produced from the fermentation of Bacillus subtilis. The solvent extraction protocol for recovery of MK-7 from fermentation media has a significant effect on the yield of process; low extraction efficiency results in loss of the product even if high concentrations are achieved during fermentation. Mixtures of 2-propanol and hexane are commonly used to extract MK-7 from fermentation media and food products. However, extraction conditions including the composition of organic solvents, volume ratio of organic to aqueous phase, and the mixing time between phases have not yet been optimized. The aim of this study was to enhance the MK-7 extraction by optimizing these parameters. The second order polynomial equation was fitted to the results by using central composite circumscribed design with R2 = 0.962 and R2(Adj) = 0.914. An optimum mixture of 2- propanol: hexane (1:2, v:v) and organic: aqueous phase ratio of (1:4, v:v) with 1 min mixing time was predicted by model. The amount of extracted MK-7 was in agreement with the values predicted by the statistical method with 58.47 mg/l, experimental and 57.25 mg/l, predicted. This is the first report on optimizing the extraction parameters for MK-7.