Hydrophobic microspheres for in situ removal of 2-phenylethanol from yeast fermentation

Yigal Achmon, Jenny Goldshtein, Shlomo Margel, Ayelet Fishman

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


The commercial production of the fragrance compound 2-phenylethanol (2-PE) from phenylalanine by yeast is limited by the accumulation of the toxic product, and therefore, in situ product removal techniques are required. We describe the use of hydrophobic polymethylmethacrylate (PMMA) microspheres of narrow size distribution of 1.53±0.10m diameter for continuous removal of 2-PE from the fermentation medium by a mechanism of swelling. In shake flask experiments with conditions simulating 2-PE stress, a 10-fold increase in productivity was measured for systems containing >10% (w/v) microspheres. A 1L fed-batch fermentation with 8% (w/v) of PMMA microspheres resulted in a total 2-PE concentration of 7.05g/L, from which 5.40g/L was incorporated inside the resin, implying 76% encapsulation. This ratio of 0.07g/g of product per resin is among the highest reported to date. Scanning electron microscopy revealed a concomitant increase in sphere diameter confirming that swelling occurred.

Original languageEnglish
Pages (from-to)628-638
Number of pages11
JournalJournal of Microencapsulation
Issue number7
StatePublished - Nov 2011

Bibliographical note

Funding Information:
This study was supported by the Russell Berrie Nanotechnology Institute at the Technion. Partial support was also provided by a Minerva Grant (Microscale and Nanoscale Particles and Films).


  • 2-phenylethanol
  • In situ product removal
  • Polymethylmethacrylate microspheres
  • Saccharomyces cerevisiae
  • Single-step swelling


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