Cr(VI) reduction by Pseudomonas aeruginosa immobilized in a polyvinyl alcohol/sodium alginate matrix containing multi-walled carbon nanotubes

► MCNTs, PVA and sodium alginate are exploited to immobilize Pseudomonas aeruginosa. ► Freeze-thawing treatment enhances the mechanical strength of immobilized cells. ► The immobilized P. aeruginosa is able to reduce Cr(VI) to soluble Cr(III). ► Consecutive reduction of Cr(VI) is easily carried out.