Department of Chemical Engineering, Biochemical Engineering Division, Bio-Technology Laboratory, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India Manuscript received 27 August 2010, accepted 15 September 2010 A study was carried out on the role or different trace elements on the production of L-glutamic acid by a mutant Micrococcus glutamicus AB100 for the selection of suitable synthetic medium. It was observed that Fe2+, Mn2+ and zn2 were required for this mutant strain. The optimum levels of Fe2+ was 5.0μg/ml and both Mn2+ and zn2+ required 1.0 µg/ml each for the production of L-glutamic acid. But other elements, namely Cu2+, Ni2+, Co2+ v3+ Fe3+ and Mo6+ had an adverse effect on L-glutamic acid accumulation by this strain. Thus, addition of necessary trace elements into the fermentation medium resulted significant (p < 0.01) increase In L-glutamic acid accumulation of 23.8 mg/ml compared to the production of this amino acid before addition of necessary trace elements into the fermentation medium (18.8 mg/ml).