In this study, a novel method to immobilize and separate Corynebacterium glutamicum for phenol degradation was developed using Fe3O4 nanoparticles (NPs). The Fe3O4 NPs were encapsulated with silica and functionalized with NH2 groups to enhance their capacity to adsorb on the cell surface. The results showed that the NH2-functionalized silica-encapsulated Fe3O4 NPs strongly adsorbed on the cell surface of C. glutamicum during 32 d culture without any interruptions of their normal cell growth. The coated C. glutamicum were easily separated from the culture broth within 2 min by applying an external magnetic field Also, the coated C. glutamicum were able to completely degrade 50 ppm phenol in the culture broth after 8 d culture at 30 degrees C. Concerning reusability, the coated cells could completely degrade phenol during the first 2 cycles, and retain similar to 60% activity of phenol degradation for the third and four cycles. (C) 2011 Elsevier Ltd. All rights reserved.