In the paper “A novel inducible protein production system and neomycin resistance as selection marker for Methanosarcina mazei” we stated that there was no inducible protein production system available for methanogenic archaea. However, Macauley et al. [1] have published an acetate-inducible gene expression system for Methanosarcina acetivorans that was successfully used to produce a carbonic anhydrase.