In situ preparation of programmable curli nanomaterials as fine-tuned sustainable supports enabling selective and oriented incorporation of enzymes

Abstract

Pollution caused by phthalic acid esters (PAEs) has shown interference with hormone homeostasis. To reduce the influence of PAEs on the environment, a two-step method for magnetic curli nanomaterial preparation was developed without excess use of high-salt solutions, which realized the selective and oriented immobilization of esterases. It was achieved by the preparation of Fe₃O₄@NiSiO₃@CsgB nanomaterials, which facilitated the anchoring, assembly, and magnetic recovery of curli nanofibers in situ without complicated post-processing. The resulting magnetic curli nanomaterials achieved the specific immobilization of esterase Est3-14(SpyCatcher) through conjugation pairing (SpyTag/SpyCatcher), with an effective enzyme loading of >329 mg g⁻¹. When tested for biodegradation reactions, ∼88% of dibutyl phthalate was degraded by immobilized esterases in 1 h. The immobilized enzyme retained over 52% of its activity after eight cycles of reuse. These results demonstrate the feasibility of the structural and property fabrication of green and sustainable curli nanomaterials for biotechnological applications.