Use of a genetic algorithm in the development of a synthetic growth medium for Arthrobacter simplex with high hydrocortisone Δ¹‐dehydrogenase activity

The production process for Arthrobacter simplex high specific hydrocortisone Δ¹‐dehydrogenase activity and biomass yield (full experimental plan: 1·5 × 10¹⁴ experiments). The specific hydrocortisone Δ¹‐dehydrogenase activity was improved by a vector of 4·5 to 1800 U g⁻¹. With the optimized medium composition in a stirred tank reactor for batch production of A. simplex, a specific hydrocortisone Δ¹‐dehydrogenase activity of 2000–3000 U g⁻¹ dry biomass was achieved depending on harvest time (previously reported data: 18–37 U g⁻¹).