Purpose: To improve the production of L-serine from sucrose directly by wild type Corynebacterium glutamicum SYPS-062.

Methods: The culture medium for the production of L-serine was optimized using a statistical experimental design. Sucrose, ammonium sulfate ((NH₄)₂SO₄) and biotin were the key factors, based on previous studies. A three-level Box–Behnken factorial design combined with response surface methodology were used to optimize the medium for the production of L-serine. Validation experiments were also carried out to establish the adequacy and accuracy of the model obtained.

Results: Under optimal conditions (sucrose 81 g/l, (NH₄)₂SO₄ 30 g/l and biotin 27 μg/l), L-serine concentration increased to 14.90 g/l which is about 2.5-fold increase over that of the original medium (6 g/l). L-serine concentration in a 5 L fermenter reached 16.4 g/L.

Conclusion: The results show that statistical medium design method is effective in improving L-serine production. The optimization medium is considered fundamental and useful for the development of C. glutamicum SYPS-062 cultivation process for efficient production of L-serine on a large scale.