Sequestration of Co(II) from aqueous solution using immobilized biomass of Nostoc linckia waste from a hydrogen bioreactor

► Biomass waste from a hydrogen bioreactor is reused as metal biosorbent. ► Co(II) removal response of immobilized cells is maximized using statistical model. ► The biosorbent is efficient at ambient temperatures and low biomass dose. ► Its biosorption capacity from dilute Co solutions is superior to others reported. ► Suggests integration of bioenergy production and bioremediation processes.