Immobilization of penicillin G acylase: The key to optimum performance

Penicillin G acylase is a major industrial biocatalyst that is used in the enzymatic production of 20,000 t a(-1) of 6-aminopenicillanic acid, the industrial P-lactam intermediate, as well as in the enzymatic production of semi-synthetic P-lactam antibiotics. Because efficient recovery and reuse of the biocatalyst is a prerequisite for a viable process, much attention has been focused on the immobilization of penicillin G acylase. Methods that have been studied and will be discussed in this review include covalent attachment to porous organic and. inorganic carriers, inclusion in and attachment to biopolymer gels and carrier-free immobilization techniques. Highly active and stable preparations have been developed; mass transfer limitations in the carrier are now a major barrier to further improvement of the biocatalyst performance.