Magnetic actuation of fungal pellets via immobilization of ferromagnetic particles

• Composite particles magnetically functionalize Aspergillus oryzae pellets. • Magnetic labelling works during growth and via short-term incubation. • Image analysis shows pellet enlargement and particle clustering. Magnetic functionalization of fungal biomass via in situ immobilization of ferromagnetic particles enables non-contact manipulation and efficient magnetic separation for process intensification in biotechnological applications. In this study, Aspergillus oryzae was cultivated in the presence of magnetite or a magnetite-activated carbon composite to promote particle incorporation during pellet growth. Morphological analysis based on image processing revealed a concentration-dependent increase in pellet size, accompanied by internal particle agglomeration. Additionally, magnetic labelling was achieved post-cultivation by incubating mature pellets with suspended particles, allowing for flexible integration into existing processes. Both approaches yielded magnetically responsive fungal biocomposites that could be readily separated using external magnetic fields, highlighting their potential for biomass retention, recovery and process intensification.