Inclusion bodies of fuculose-1-phosphate aldolase as stable and reusable biocatalysts.

Abstract

Fuculose-1-phosphate aldolase (FucA) has been produced in Escherichia coli as active inclusion bodies (IBs) in batch cultures. The activity of insoluble FucA has been modulated by a proper selection of producing strain, culture media, and process conditions. In some cases, when an optimized defined medium was used, FucA IBs were more active (in terms of specific activity) than the soluble protein version obtained in the same process with a conventional defined medium, supporting the concept that solubility and conformational quality are independent protein parameters. FucA IBs have been tested as biocatalysts, either directly or immobilized into Lentikat beads, in an aldolic reaction between DHAP and (S)-Cbz-alaninal, obtaining product yields ranging from 65 to 76%. The production of an active aldolase as IBs, the possibility of tailoring IBs properties by both genetic and process approaches, and the reusability of IBs by further entrapment in appropriate matrices fully support the principle of using self-assembled enzymatic clusters as tunable mechanically stable and functional biocatalysts.