Polysaccharide-layered double hydroxide-aldolase biohybrid beads for biocatalysed CC bond formation.
Résumé
This study describes the design a novel microbioreactor for the biocatalysed asymmetric synthesis of polyhydroxylated compounds. The bioreactor was elaborated by a hierarchical assembly of a recombinant fructose-6-phosphate aldolase (FSAwt), layered double hydroxides (LDH) nanoplatelets and polysaccharide beads. Various polysaccharides were tested to encapsulate FSAwt and pre-immobilised FSAwt in LDH (FSAwt@Mg2Al-LDH). ι-Carrageenan appears as the most suitable candidate to prepare biohybrid beads. The retained activities in ι-carrageenan beads were measured for both free FSAwt and immobilised FSAwt revealing a 3 fold higher activity in favour of the pre-immobilised FSA. This result was probably due to a positive interaction between the negatively charged polysaccharide and the positively charged LDH layers. The catalytic activity, the recyclability and the storage of the beads were studied in addition to the leakage of FSAwt activity from beads. Nanostructuration of both FSAwt/ι-carr and FSAwt@Mg2Al-LDH/ι-carr was investigated by structural and textural characterization techniques.