Bioproduction of 2-phenylethanol in a biphasic ionic liquid aqueous system

Area of Science:

• Biotechnology
• Chemical Engineering
• Microbiology

Background:

• 2-Phenylethanol (PEA) is a valuable fragrance and flavor compound.
• Saccharomyces cerevisiae produces PEA but suffers from low yields due to product inhibition.
• In situ product removal (ISPR) is a strategy to overcome low yields.

Purpose of the Study:

• To investigate the use of immiscible ionic liquids (ILs) in a biphasic system for enhanced PEA production via ISPR.
• To identify biocompatible ILs and understand structure-activity relationships for yeast growth.
• To evaluate the PEA recovery capability and ISPR efficiency of selected ILs.

Main Methods:

• Screening of nine ILs for biocompatibility with Saccharomyces cerevisiae.
• Correlation analysis of IL structure (anion, cation, alkyl chain length) with yeast growth.
• Determination of distribution coefficients (K(D)) for PEA recovery.
• Testing ILs as ISPR solvents under high product concentration stress.

Main Results:

• Five ILs demonstrated biocompatibility with yeast.
• [Tf(2)N] anions and pyridinium/ammonium cations showed better biocompatibility than [PF(6)], [BF(4)], and imidazolium cations.
• BMIM[Tf(2)N] exhibited the highest PEA distribution coefficient (17.6).
• MPPyr[Tf(2)N], OMA[Tf(2)N], and BMIM[Tf(2)N] achieved a 3-5 fold increase in total PEA concentration.

Conclusions:

• Ionic liquids can be effectively used in biphasic systems for ISPR of PEA.
• Biocompatible ILs with specific structural features can significantly enhance PEA production yields.
• This approach demonstrates the potential of ILs for improving productivity in microbial bioprocesses.