Fermentative production of L-proline with auxotrophs of Corynebacterium glutamicum.

Abstract

Two auxotrophic mutants of Corynebacterium glutamicum were found to produce a large amount of l-proline in the culture medium. High concentration of MgSO4 or MnSO4 in the medium stimulated the l-proline production by an isoleucine auxotroph. Optimum concentration of l-isoleucine was 200 μg/ml, and the higher concentration of l-isoleucine reduced the l-proline production. The auxotroph produced 14.8 mg/ml of l-proline when cultured in a medium containing 12% glucose, 1.7% NH4C1,0.6% MgSO4·7H2O, 0.06% MnSO4·4H2O and 200 μg/ml of l-isoleucine. The other mutant, whose growth responds to the bases of nucleic acids, produced 7 to 13 mg/ml of l-proline in a cane molasses (15%, as glucose concentration)-medium containing 2% of the acid-hydrolyzate of soybean meal. The l-proline production by this mutant increased to a level of 27 to 31 mg/ml when the growth was suppressed by the addition of 4% NH4C1 to the medium, or by the addition of 2 mg/ml of polyoxyethylenestearylamine, a surfactant, to a culture at an appro...