Mineral salts in medium usually profoundly influence microorganism growth and protein synthesis. In order to produce microbial transglutaminase (MTG) with a high yield from Streptoverticillium mobaraense, we screened the minerals $CaCl_2,;CoCl_2,;FeSO_4,;ZnSO_4,;MnSO_4;and;CuSO_4$ for MTG fermentation. The results indicated that appropriate $FeSO_4$ concentrations could significantly promote cell growth and stimulate the production of MTG. With 15 mg/L of $FeSO_4$ added to medium, 58% improvements were noted in MTG productivity (2.24 U/mL). NaCl, $CaCl_2,;and;CoCl_2$ enhanced MTG productivity by less than 15%, and the optimal concentrations were determined as 1 g/L, 2 g/L, and 30 mg/L respectively. Furthermore, it was determined that 7.5 mg/L of $ZnSO_4$ in medium could augment MTG productivity by 20% and induce the stationary phase for MTG production to a period 24 hr earlier. This basic and novel discovery should result in the development of a good complement to the previously defined culture media for MTG fermentation.