Economical production of vitamin K2 using wheat starch wastewater

In order to reduce the production cost of vitamin K-2, wheat starch wastewater was used to produce vitamin K-2 using Bacillus subtilis W-17. The starch and protein in effluent could reduce the amounts of carbon and nitrogen sources in the medium. The liquefied wheat flour replaced glycerol as an external carbon source. The phosphate in wheat starch wastewater could meet the needs of B. subtilis W-17. Wheat starch wastewater was used as a process water. The Response surface methodology (RSM) was then employed to optimize the medium of producing vitamin K-2, and the result was as follows: 16.1% wheat flour, 14.3 g/L soybean peptone and 26.4 g/L soybean meal. Under this condition, the vitamin K-2 production was increased to 41.43 mg/L. The fermentor test further proved that the use of wheat starch wastewater had a little effect on the growth of B. subtilis and vitamin K(2 )synthesis. This process saved 33% of the carbon source cost, 7% of the nitrogen source cost, 100% of the phosphate and process water costs. As all waste came from food factories, the safety of products and the psychological acceptance of consumers were higher. In addition, the process could offset the disposal costs of wheat starch wastewater. These investigations would lay the foundation for reducing the pollution of wheat starch wastewater, exploring a late-model for cleaner vitamin K-2 production. (C) 2020 Elsevier Ltd. All rights reserved.