Novel synthetic pathways were designed for the synthesis of γ-CD from the non-food feedstock cellulose via an in vitro adenosine triphosphate (ATP) –free synthetic enzymatic biosystem. Cellulose was employed as the substrate for producing cellobiose, which was subsequently converted to γ-CD via a cascade reaction utilizing five enzymes. A stoichiometric conversion of cellulose to γ-CD was achieved by adding the synthesis module for glucose-1-phosphate (G-1-P) and optimizing the reaction conditions.
The CGT from Evansella clarkii was found to convert starch to α-, β-, and γ-CD with a ratio of 0:11:89. However, a ratio 0:3:97 of α-, β-, and γ-CD was obtained when the enzymes CBHI, CBP, AGP, PPGK, PGM, and CGT were employed for γ-CD production using cellulose as the substrate. This resulted in the production of γ-CD of high purity (95.8 %). The conversion rate of cellulose reached 91.5 %, while cellobiose was completely converted under its optimal conditions, indicating the high efficiency of CBHI and CBP. The percent yields of α-, β-, and γ-CD relative to cellulose were 0 %, 0.1 %, and 5.9 %, respectively. The productivity was enhanced by introducing a G-1-P module and optimizing the reaction conditions. This resulted in a remarkable γ-CD productivity of 517 g/m3·h from cellobiose
Kangle Niu, Ziyuan Ni, Shiyu Yuan, Zixian Wang, Xu Fang (2025) One-pot synthesis of γ-cyclodextrin of high purity from non-food cellulose via an in vitro ATP-free synthetic enzymatic biosystem. Carbohydrate Polymers 347, 122735. https://doi.org/10.1016/j.carbpol.2024.122735.
Featured drawing: Crini, Review: a history of cyclodextrins, Chem. Rev. 114 (2014) 10940e10975.