Optimisation of reaction conditions for production of S-(-)-2-hydroxypropiophenone by Acinetobacter calcoaceticus

Abstract

Whole cells and cell-free extracts of Acinetobacter calcoaceticus containing benzoylformate decarboxylase efficiently condensed benzoylformate and acetaldehyde to produce the acyloin compound S-(-)-2-hydroxypropiophenone. Optimal concentrations of acetaldehyde cosubstrate for this reaction were found to be 1600 and 800 mM when whole cells and cell-free extracts were used respectively as biocatalysts. In both cases, optimal benzoylformate concentration was 100 mM. Temperature and pH optima for the biotransformation reaction were 30°C and 6.0 respectively. Under optimised conditions, maximum production of 2-hydroxypropiophenone, amounting to 8.4 g L-1, occurred after a 2-h incubation. Product formation equivalent to 6.95 g in 1 h corresponded to a productivity of 267 mg acyloin per g dry cells per h. © 1994 Society for Industrial Microbiology.