Economic conversion of spirit-based distillers’ grain to 2,3-butanediol by Bacillus amyloliquefaciens

• Spirit-based distillers’ grain (SDG) was firstly used to produce 2,3-butanediol.
• Starch could be directly converted into 2,3-BD by Bacillus amyloliquefaciens.
• Additional supplementation of commercial sources of nutrients was not necessary.

Spirit-based distillers’ grain (SDG), a waste eluted from the Chinese spirit-making process, is rich in starch, nitrogen, water-soluble vitamins, amino acids, minerals, and other growth stimulants. In this work, we investigated the use of SDG as feedstock for the fermentative production of 2,3-butanediol (2,3-BD). Hydrolysis of the waste SDG was not necessary, and it was directly used as a substrate by Bacillus amyloliquefaciens B10-127 to produce 2,3-BD. Exogenous nitrogen sources had little stimulating effect on 2,3-BD production, demonstrating that SDG requires no supplementary nutrient source for successful conversion. A productivity of 0.81 g/L/h was achieved, which is the highest reported result for productivity of 2,3-BD with SDG waste material as the fermentation medium. We suggest that raw SDG can be used as the sole source of C and N in a commercially viable process to produce 2,3-BD.