Biotransformation of 2-phenylethanol to phenylacetaldehyde in a two-phase fed-batch system

摘要

Phenylacetaldehyde (PA) can be produced by the oxidation of 2-phenylethanol (PE) through biotransformation.In order to prevent substrate and product inhibitions and the transformation of the PA to phenylacetic acid (PAA),utilization of a two-phase system is very attractive.Gluconobacter oxydans B-72 was used as the microorganism and iso-octane as the solvent.The effect of initial substrate concentration on the PA production was investigate in single-and two-phase systems.In the single-phase system,substrate inhibition occurred aobve 5 g/l,and in the two-phase system,above 7.5 g/l.Substrate inhibition kinetics were also studied in the two-phase system is insufficient to remove the substrate inhibition effect,fed-batch operation was utilised in this study.For 7.5 g/l of PE,1.65,3.85,and 7.35 g/l of PA were obtained in the single-phase,two-phase,and two-phase three fed-batch systems,respectively.Effect of biotransformation time,initial substrate concentration,agitation speed,and fed-batch number of the PA production was investigated in a two-phase fed-batch system by the response surface methodology (RSM).The optimum values were found as 3 fed-batch number,2.76 g/l initial substrate concentration,150 rpm agitation speed,and 65 mino of one batch biotransformation time.In order to verify these results,an experiment was performed at these optimum conditions and 7.10 g/l of PA cocnentration was obtained.