In-situ microextractive adsorption of α-pinene from fermentation broths by a recombinant yeast

α-Pinene, a promising advanced biofuel, has garnered significant attention in the field of synthetic biology. However, its high cytotoxicity and volatility pose substantial challenges for efficient recovery from fermentation broths. This study explores a novel solid–liquid phase microextractive adsorption (SLPMA) technique to achieve in-situ separation of α-pinene from fermentation broths using a recombinant yeast. The extractant was immobilized into a polystyrene (PS) skeleton through copolymerization to prepare six resins for in-situ microextractive adsorption of α-pinene in the fermentation broth. The optimal extractant, isopropyl myristate (IPM), incorporated into the PS resin (PS-IPM) exhibited acceptable biocompatibility. Comprehensive characterization of the PS-IPM resin using FTIR, SEM, nitrogen physisorption, and TGA confirmed the successful immobilization of IPM (41.39 wt%) and material suitability. Compared to traditional extractive fermentation methods, the SLPMA process significantly enhanced cell growth promotion efficiency by 4.5 times. This improvement is attributed to the immobilization of the extractant within the porous material, which increased the extraction interface area and induced a microextraction effect. This effect enriched the α-pinene concentration in the regular fermentation broth toward the IPM phase of the PS-IPM microextractor by 57.9-fold. It increased the α-pinene concentration by 2.3-fold compared to the IPM from the extractive fermentation system. Consequently, the PS-IPM resin exhibited outstanding performance and effectively mitigated product inhibition. The resin successfully facilitated multiple cycles of in-situ α-pinene separation during fermentation, achieving a recovery of up to 95.82%. Furthermore, the removal efficiencies for inorganic salts, pigments, and proteins in the fermentation broth exceeded 98%. A delayed resin addition strategy was also implemented, further enhancing operational efficiency. FTIR analysis, combined with quantum chemical calculations, revealed that the strong van der Waals interaction is the primary driving force behind the separation process. This interaction enables the PS-IPM resin to function as an effective microextractor during adsorption. The study highlights the considerable potential of the SLPMA process for in-situ α-pinene separation during fermentation, providing a valuable reference for addressing challenges in other product-inhibited fermentation systems.