The effects of polymer phase ratio and feeding strategy on solid–liquid TPPBs for the production of l-phenylacetylcarbinol from benzaldehyde using Candida utilis

Abstract

To increase the bioproduction of L-phenylacetylcarbinol (PAC), a precursor molecule in the synthesis of the decongestants ephedrine and pseudoephedrine and which suffers from substrate, product, and by-product inhibition, by ensuring that the delivery of the substrate, benzaldehyde, is maintained within a strict concentration window. Beads of the commercial polymer, Hytrel G3548L, can act as a sequestering phase to reduce inhibitory effects to cells of Candida utilis while creating a reservoir for high concentrations of products. In this work we varied the polymer phase volume ratio (from 3 to 15%), and modified the benzaldehyde feeding strategy to further improve on system performance, resulting in greater than 100% increase in the PAC productivity relative to a single phase control, as well as robust operation of the two-phase bioreactor with minimal operator intervention.