Development of a scalable semi-synthetic medium for high-yield diphtheria toxin production using a definitive screening design an innovative statistical optimization method

<i>Corynebacterium diphtheriae</i> is the causative agent of diphtheria, which continues to be a serious health risk to children, particularly in countries such as India. Immunization is the best way to fight this illness. Enhancing the synthesis of diphtheria toxin (DT) is essential for the production of vaccines, particularly as immunization programs advance. Pork digestion medium (PDM) was employed as the standard medium for DT production. Nevertheless, this medium has issues with contamination and batch-to-batch variation. The production of DT is extremely low in the alternative synthetic medium. Compared to synthetic media, semi-synthetic media exhibit superior performance. This study’s current goal was to increase DT production through the use of the Definitive Screening Design (DSD) methodology to optimize the composition of semi-synthetic media. A total of 11 components were selected for screening of the best suitable components for DT production. NZ-amine, tryptone N1, and maltose had the highest effects on DT production out of all the nutrients that were chosen. The model accuracy is indicated by the R² value of 0.9820, which enables the prediction of DT yields. The model suggests the lower concentrations of NZ-amine combined with the moderate amounts of maltose and tryptone N1 is best suitable for the higher amounts of DT yields. With optimized conditions 174 Lf/mL of DT yield was achieved in validation experiments, which is nearer to the PDM yields. According to this study, this enhanced technique, which makes use of an affordable and expandable medium, could make large-scale toxoid production feasible.