Plug-in Assembly of a Surface-Displayed Cellulolytic Arsenal and Evaluation of Its Effects on the Saccharification of Lignocellulosic Material

Due to their highly efficient bioconversion of lignocellulosic biomass, the design and development of artificial cellulosomes are of tremendous interest. In this study, we displayed a designed scaffoldin, comprising three tandem peptides split from SpyRing, SnoopRing, and DogRing, on the Escherichia coli BL21 (DE3) cell surface by fusing to curli fiber protein CsgA. Subsequently, an artificial cellulosome was constructed by recruiting carbohydrate-active enzymes (CAZymes) with diverse acting modes, including xylanase TfXYN11, glucanase IDSGLUC5, lytic polysaccharide monooxygenase BsLPMO10A, and ferulic acid esterase AmFAE1A, via isopeptide-mediated ligation. Importantly, plug-and-socket assembly of the cellulosome was achieved within 5 min over broad pH (2.2-9.0) and temperature (0-37 °C) ranges. The engineered BL21:ΔCsgA/ASC anchored to the designed cellulosome was catalytically proficient against plant-derived polysaccharides glucan and xylan in terms of both activity and reusability. In addition, BL21:ΔCsgA/ASC catalyzed the saccharification of wheat straw, providing novel strategies for consolidated bioprocessing and the development of feed additives.