Selection of Suitable Maintenance Medium and Determination of Auxotrophic Nature of the Multiple Analogue Resistant Mutant Micrococcus glutamicus X₃₀₀ for L-methionine Fermentation

The present study was conducted to select a suitable maintenance medium for the maintenance of the multiple analogue resistant mutant and also to determination of its auxotrophic requirements. Among the three medium studied, the strain maintained its constant rate of production of L-methionine for many generations(studied up to 12 months) with glucose, 20 gm/L; (NH₄)₂SO₄; 1.6 gm/L; NaCl, 2.5gm/L; MgSO₄.7H₂O,0.25 gm/L; MnSO₄.4H₂O, 0.1 gm/L; K₂HPO₄, 1.0 gm/L; KH₂PO₄,1.0 gm/L; biotin, 2μg/ml; thiamine-HCl, 2μg/ml and agar 2% as a solidifying agent which can prevent its degeneration. This strain thus showed double auxotrophic requirements for both biotin and thiamine-HCl.