Background
Type: Article

Biotransformation of benzaldehyde to L-phenylacetyl carbinol using immobilized cells of Saccharomyces cerevisiae

Journal: Minerva Biotecnologica (11204826)Year: March 2015Volume: 27Issue: Pages: 43 - 49
Doostmohammadi M. Esfandiari M.Asadollahi M.aKamali M.a Nahvi I.
Language: English

Abstract

Aim. The main goal of the present study was to study biotransformation of benzaldehyde to L-phenylacetyl carbinol (L-PAC) by free and immobilized cells of Saccharomyces cerevisiae. Yeast cells were immobilized both in calcium alginate and calcium alginate-PVAboric acid beads. Methods. Yeast cells were immobilized with calcium alginate and calcium alginate-PVA-boric acid beads. Free or immobilized cells were added to biotransformation medium containing benzaldehyde and acetaldehyde and incubated at 30 °C and 200 rpm in anaerobic conditions. Samples were taken every two hours. Concentrations of benzaldehyde, L-PAC, and benzyl alcohol were determined by gas chromatography. Effect of benzaldehyde concentration on L-PAC formation was investigated. Fed batch fermentation was performed using immobilized yeast cells in a 3 L bioreactor. Results. The optimum biotransformation of benzaldehyde to L-PAC was obtained at 2 g/L of benzaldehyde. Cells immobilized in calcium alginate-PVA beads produced approximately 2 g/L of L-PAC using 2 g/L of benzaldehyde in the second and third cycles. In fed batch fermentation, a concentration of nearly 3 g/L L-PAC was achieved. The highest obtained yields of L-PAC for free cells, immobilized cells in calcium alginate, immobilized cells in calcium alginate-PVA-boric acid, and fed batch fermentation were 0.55, 0.55, 1, and 0.64 g L-PAC per each gram of consumed benzaldehyde, respectively. Conclusion. This study showed that higher L-PAC titers can be obtained using immobilized yeast cells. Besides improved mechanical properties, cells immobilized in calcium alginate-PVA-boric acid beads exhibited higher production of L-PAC and lower amount of benzyl alcohol as compared to the cells immobilized in calcium alginate beads. © Copyright 2016 Edizioni Minerva Medica.