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3002010 
Journal Article 
Biotransformation of benzaldehyde to L-phenylacetyl carbinol using immobilized cells of Saccharomyces cerevisiae 
Doostmohammadi, M; Esfandiari, M; Asadollahi, MA; Kamali, M; Nahvi, I 
2015 
1 
Minerva Biotecnologica
ISSN: 1120-4826 
Edizioni Minerva Medica 
27 
1 
43-49 
English 
WOS:000358106800006 
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-PVA-boric 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 degrees 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. 
Saccharomyces cerevisiae; Biotransformation; Benzaldehyde