Permeable and robust polymer-silica hybrid armor on cell catalyst for sustainable biomanufacturing

Abstract

Inactivated cell catalysis is one of several central techniques in green biomanufacturing realm. However, the instability and leakage of enzymes in inactivated cell severely restrict the practical applications of inactivated cell catalysis. Constructing armor on the surface of inactivated cells affords a feasible and effective strategy to enhance the stability of cells while commonly lowering the permeability. Herein, polymer-silica hybrid armor (PSHA) is directly generated on the surface of enzyme-containing cells. The branched structure of PEI enables higher porosity of cell@PSHA, exhibiting 1.52-fold enhancement in substrate permeability by contrast with cell@silica armor (SA). The electrostatic interactions (NH3+ with O-) and hydrogen bonding (N···H or O···H) interactions between structural units enables higher stability of cell@PSHA, showing 3.13-fold elevation in Young's modulus compared with cell@SA. As a result, the cell@PSHA can catalyze continuous conversion of starch to tagatose for 15 batches over 969 h, with an average yield of 77.76 g L-1.