Sulfur mustard (SM) can be hydrolyzed by haloalkane dehalogenases such as DhaA, LinB and DmbA. However, the low resistance to the elevated temperatures limited the practical application of haloalkane dehalogenases. Here we reported a new thermotolerant dehalogenase FM2382 from Fulvimarina manganoxydans sp. nov. 8047. The specific activity of FM2382 to SM is 0.6 U/mg. FM2382 possessed high heat stability (45 degrees C) in slight alkali environment (pH 7.5) and retained approximately 50% activity after incubation at 70 degrees C for 40 min. The catalytic activity of FM2382 was activated by Co2+ and Mg2+, and inhibited by Zn2+, Cu2+ and Fe3+. Furthermore, site-specific mutagenesis proved that D34, K207 D232, D237 were amino acid residues related to the catalytic activity of SM. In conclusion, we found a thermostable haloacid dehalogenases (HAD) family dehalogenase showing SM-degradation activity, which may be useful for practical application in the future. (C) 2017 Published by Elsevier Inc.