A new marine bacterial laccase with chloride-enhancing, alkaline-dependent activity and dye decolorization ability

► A new bacterial laccase (lac21) was obtained from a marine metagenome. ► Lac21 shares less than 40% of sequence identities among all of the laccases found. ► Lac21 displays alkalescence-dependent activity and stability. ► Chloride stimulated laccase activity by enhancing the affinity of Lac21 to substrate. ► Eighty percentage of dye decolorization was achieved in 24 h without mediators at room temperature.