Comparative study on Ni2+-affinity transport of nickel/cobalt permeases (NiCoTs) and the potential of recombinant Escherichia coli for Ni2+ bioaccumulation

► Two kinds of NiCoTs were comparatively studied on their Ni2+ transport ability. ► Expression of NiCoT made recombinant strains more sensitive to the toxicity of Ni2+. ► NixA from Helocobacter pylori had a higher Ni2+-affinity than NisA from Staphylococcus aureus. ► Recombinant Escherichia coli expressing NixA and MT accumulated maximum Ni2+ of 83.33 mg g−1. ► Both NiCoT and MT were essential for Ni2+ bioaccumulation of recombinant strains.