A Bacillus licheniformis mutant host cell derived from a parent B. licheniformis host cell, which mutant host cell is mutated in one or more gene(s) encoding one or more secreted polypeptide(s) which is at least 80% identical to one or more of the polypeptides shown in SEQ ID NO 166, wherein the mutant host cell secretes at least 5% less of the one or more secreted polypeptide(s) than the parent host cell, when they are cultivated under comparable conditions.