Development of menaquinone-7 enriched nutraceutical: inside into medium engineering and process modeling

Menaquinone 7 (MK-7) is nutritionally important metabolite found by fermentation mainly using B. subtilis species. In this study, soybean medium was modified to improve the MK-7 production using Bacillus subtilis NCIM 2708 under solid state fermentation. The objective of this study was to produce large amount of MK-7 within a short period of time. Nine nutritional components viz. glycerol, mannitol, dextrose, sucrose, yeast extract, malt extract, K2HPO4, MgSO4.7H2O and CaCl2 were investigated to obtain the maximum MK-7 concentration. The highest MK-7 concentration 39.039 μg/g was obtained after 24 h of fermentation in the following optimised medium components: soybean 20 g, glycerol 40 ml/kg, mannitol 60 g/kg, yeast extract 4 g/kg, malt extract 8 g/kg and calcium chloride 4 g/kg. The maximum production of MK-7 56.757 μg/g was predicted by point prediction tool of Design Expert 7.1 software (Statease Inc. USA). This data shows 68.78 % validity of the predicted model.