A novel and environment-friendly bioprocess of 1,3-propanediol fermentation integrated with aqueous two-phase extraction by ethanol/sodium carbonate system

•Developing an efficient integrated system of fermentation and separation by ATPS.•The system can dramatically increase the fermentation and separation efficiency.•The system could recover most of salt.•The system could dramatically reduce the energy expenditure and CO2 emissions.

An integrated fermentation–separation process for the production of 1,3-propanediol (1,3-PD) was investigated. Aqueous two-phase system (ATPS) not only recovered 97.9% of 1,3-PD, but simultaneously also removed 99.1% cells, 81.9% proteins, 75.5% organic acids, and 78.7% water. Furthermore, after extraction the bottom phase of ATPS was used to adjust the pH of the culture during fermentation, leading to 16% and 126% increases in the concentrations of 1,3-PD and lactic acid, and dramatic decreases in the concentration of acetic acid and formic acid. The total mass conversion yield of three main products (1,3-PD, 2,3-butanediol, and lactic acid) from glycerol reached 81.6%. The salt-enriched phase could also be used to absorb carbon dioxide (CO2), resulting in 94% recovery for carbonate. Finally, process simulation using the program PRO/II showed the use of ATPS reduced 75.1% of the energy expenditure and 89.0% of CO2 emissions.