Cross-linked cyclodextrin glucanotransferase aggregates from Bacillus lehensis G1 for cyclodextrin production: Molecular modeling, developmental, physicochemical, kinetic and thermodynamic properties

Type of cross-linking agents influence the stability and active cross-linked enzyme aggregates (CLEA) immobilization. The information of molecular interaction between enzyme-cross linker is not well explored thus screening wide numbers of cross-linker is crucial in CLEA development. This study combined the molecular modeling and experimental optimization to investigate the influences of different cross-linking agents in developing CLEA of cyclodextrin glucanotranferase G1 (CGTase G1) for cyclodextrins (CDs) synthesis. Seven types of cross-linkers were tested and CGTase G1 cross-linked with chitosan (CS-CGTG1-CLEA) displayed the highest activity recovery (84.6 +/- 0.26%), aligning with its highest binding affinity, radius of gyration and flexibility through in-silico analysis towards CGTase G1. CS-CGTG1-CLEA was characterized and showed a longer half-life (30.06 +/- 1.51 min) and retained a greater thermal stability (52.73 & PLUSMN; 0.93%) after 30 min incubation at optimal conditions compared to free enzyme (10.30 +/- 1.34 min and 5.51 +/- 2.10% respectively). CS-CGTG1CLEA improved CDs production by 33% and yielded cumulative of 52.62 g/L CDs after five cycles for 2 h of reaction. This study reveals that abundant of hydroxyl group on chitosan interacted with CGTase G1 surface amino acid residues to form strong and stable CLEA thus can be a promising biocatalyst in CDs production.

Automated summary

This study investigates the influence of different cross-linking agents on the immobilization of cyclodextrin glucanotransferase G1 (CGTase G1) for cyclodextrin synthesis. Through molecular modeling and experimental optimization, it is found that CGTase G1 cross-linked with chitosan (CS-CGTG1-CLEA) exhibits the highest activity recovery and stability, making it a promising biocatalyst for cyclodextrin production.