Constructing a Continuous Flow Bioreactor Based on a Hierarchically Porous Cellulose Monolith for Ultrafast and Nonstop Enzymatic Esterification/Transesterification

Continuous flow bioreactors have received increasing attention due to their automated high-throughput continuous processing. Cellulose acetate (CA), which is ecofriendly, renewable, and easily accessed, was made into monoliths with interconnected macropores and mesopores on the skeleton by the method of thermally induced phase separation (TIPS). A continuous flow bioreactor was prepared by the immobilization of lipase on the skeleton of CA monolith (CA-MN). Benefiting from the hierarchical structure, the monolith skeletons with mesopores (15.6 nm) serve as a suitable space for lipase immobilization, and the interconnected macropores (3-5 mu m) with controllable permeability make the accommodated lipase more accessible to the substrates. Based on this monolithic bioreactor, an ultrafast more than 90% conversion was developed. Compared to conventional batch reaction modes, the kinetic parameter V-m/K-m increased by 66.4-fold, and the catalysis effect (CE) increased by 6.1-fold. The monolithic continuous flow bioreactor (MCFB) enabled enzymatic esterification/transesterification to be completed in 10 min and to continue uninterrupted for 200 h, which set the highest productivity record for phytosterol esters (422 g/g monolith) without loss of catalytic activity. The novel MCFB with high catalytic activity, high stability, easy separation, scale-up, and automation introduces new expectations for sustainable development of industrial catalysis.