Integrated Aqueous Two-Phase Extraction–Distillation Strategy for Efficient 2,3-Butanediol Recovery from Fermentation Broth

The large-scale production of 2,3-butanediol (2,3-BD) is limited by the energy-intensive and costly downstream purification of fermentation broth (FB). This study presents an integrated aqueous two-phase extraction–distillation (IATPED) strategy for sustainable and efficient recovery of 2,3-BD. A systematic screening of aqueous two-phase systems composed of various organic solvents and inorganic salts identified the butyl alcohol (BuOH)/K2HPO4 system as the most effective, offering superior distribution behavior and recyclability. Process optimization using central composite design–response surface methodology (CCD–RSM) revealed that 30% (w/v) K2HPO4, 30% (v/v) BuOH, and 40 °C provided the optimal extraction conditions, yielding a distribution coefficient of 8.13 and an extraction yield of 89.60%, exceeding theoretical predictions by 1.48%. The organic-rich phase was then distilled to concentrate the 2,3-BD. Scale-up trials confirmed high extraction yield and recovery of 2,3-BD of 98.25 and 98.49% (≥99% purity), respectively, across two consecutive cycles. Furthermore, methanol-assisted crystallization enabled 98% K2HPO4 recovery. The developed process demonstrated favorable green metrics (PMI = 28.8, E-factor = 27.8, Total energy = 2.1 kWh/kg 2,3-BD), confirming its environmental and operational efficiency. The IATPED technique demonstrates a practical and effective solution for the recovery of 2,3-BD from FB.