Economical production of vitamin K(2) using crude glycerol from the by-product of biodiesel

Industrial waste, such as crude glycerol, was used for vitamin K(2) by B. subtilis Z-15. Crude glycerol could be used instead of pure glycerin for vitamin K(2) production. The combination of soybean peptone and yeast extract was more conducive to the synthesis of vitamin K(2). The optimal composition of medium was obtained by response surface methodology. The results indicated that the optimal medium was as follows: 6.3% crude glycerol, 3.0% soybean peptone concentration and 5.1 g/L yeast extract. Under the optimal culture medium, vitamin K(2) production was increased to 45.11 ± 0.62 mg/L. The fermentor test further proved that the use of crude glycerol affected neither the synthesis of vitamin K(2) nor the growth of B. subtilis. These investigations could lay a foundation for reducing the pollution of crude glycerol, exploring a late model for vitamin K(2) cleaner production.