Systematic process optimization for enhanced biosynthesis of 2-phenylethanol using Candida sorboxylosa.

2-phenylethanol (2-PE) is a high-value aromatic alcohol characterized by its rose-like fragrance, widely used in the cosmetic, food, and flavour industries. The commercial 2-PE produced via chemical routes represents considerable drawbacks, including environmental pollution, prompting interest in eco-friendly microbial alternatives. This study focused on improving the microbial production of 2-PE via Candida sorboxylosa under batch fermentation, with emphasis on a series of studies using a one-variable-at-a-time (OVAT) technique on optimizing conditions such as pH, dissolved oxygen (DO), temperature, and L-phenylalanine (L-Phe) concentration. The ideal fermentation conditions were determined as pH 5.5–6.0, the temperature 30 °C, the DO 10% after the first growth phase, and 7 g/L of L-Phe for a maximum 2-PE titer of 4.71 g/L, with a productivity of 0.095 g/L/h. The strain also exhibited a high tolerance level to 2-PE, sustaining growth even at concentrations of 5 g/L (0.5% v/v), representing the highest tolerance levels reported to date for wild-type yeast strains. Scanning electron microscopy (SEM) revealed visible changes in cell morphology at concentrations exceeding 5 g/L, signifying the onset of stress responses. The strain’s resilience highlights its promise for industrial-scale 2-PE production. Additionally, the in-house synthesized 2-PE (> 98% purity) was assessed using a metal oxide semiconductor (MOS)-based electronic nose system, confirming its sensory profile comparable to commercially available standards.