Magnetic artificial spores for robust interfacial biodesulfurization in pickering emulsions

Whole-cell Pickering interfacial biocatalysis effectively overcomes the formidable mass-transfer limitations of hydrophobic substrates in aqueous systems. However, practical implementation is severely hindered by biocatalyst vulnerability under extreme industrial environments and the inherent challenge of post-reaction emulsion separation. Herein, the artificial spore concept is specifically adapted to overcome biodesulfurization bottlenecks by sequentially encapsulating Gordonia sp. WQ-01A cells with a conformal polydopamine layer and oleic acid-modified magnetic nanoparticles. The biomimetic encapsulation establishes a protective shell that significantly shields the biocatalyst from intense ultraviolet irradiation, high concentrations of organic solvents, and extreme temperature fluctuations. Concurrently, the hydrophobic outward-facing aliphatic chains drive the spontaneous assembly of ultra-stable water-in-oil Pickering emulsions, providing an expansive interfacial microhabitat for deep biodesulfurization of dibenzothiophene. Importantly, the incorporated superparamagnetic responsiveness enables rapid liquid-liquid phase separation and catalyst recycling via a low-intensity external magnetic field, avoiding the need for energy-intensive and unscalable centrifugation operations. Although the dense hierarchical coating inevitably introduces a transient transmembrane diffusion barrier that manifests as a minor initial kinetic lag phase, this phenomenon represents a practical strategic compromise. Exchanging a brief initial mass transfer delay for enduring operational stability, mitigated product toxicity, and simplified downstream recovery allows the engineered artificial spores to maintain stable and high cyclic desulfurization activity. This engineered platform establishes a functional foundation for robust and readily recoverable multiphase biocatalysis, enabling scalable applications in complex environments.