Bioprocess and biosystems engineering

Mandelic acid chiral separation utilizing a two-phase partitioning bioreactor built by polysulfone microspheres and immobilized enzymes.

PMID 25214443


A novel two-phase partitioning bioreactor (TPPB) modified by polysulfone (PSF) microspheres and immobilized enzyme (novozym-435) was formed, and the resulting TPPB was applied into mandelic acid chiral separation. The PSF microspheres containing n-hexanol (named PSF/hexanol microspheres) was prepared by using the phase inversion method, which was used as the organic phase. Meanwhile, the immobilized enzyme novozym-435 was used as a biocatalyst. The water phase was composed of the phosphate buffer solutionxa0(PBS). (R, S)-Methyl mandelate was selected as the substrate to study enzymatic properties. Different reaction factors have been researched, such as pH, reaction time, temperature and the quantity of biocatalyst and PSF/hexanol microspheres added in. Finally, (S)-mandelic acid was obtained with an 80xa0% optical purity after 24xa0h in the two-phase partitioning bioreactor. The enantiomeric excess (eep) values were very low in the water phase, in which the highest eep value was only 46xa0%. The eep of the two-phase partitioning bioreactor had been enhanced more obviously than that catalyzed in the water phase.