Leveraging Plant Peptones In Culture Media: Productivity Measured Via Plasmid Copy Number And Fold Induction

This study investigates the application of plant-derived peptones as alternatives to animal-origin media components in biopharmaceutical fermentation, using Escherichia coli strains DH5α and EPI300 as model systems. The work addresses key industry challenges, including variability in culture performance, contamination risks, supply chain instability, and regulatory initiatives encouraging the reduction of animal-derived materials. Experimental evaluations compared soy- and pea-based protein hydrolysates with conventional tryptone, assessing parameters such as plasmid copy number, plasmid yield, and fold induction.

Results demonstrate that plant-derived peptones achieve comparable or superior cell growth and plasmid productivity relative to tryptone. Furthermore, the data reveal distinct effects on basal and induced expression levels, particularly with carbohydrate-containing peptones influencing the AraC/pBAD induction system. Carbohydrate-free hydrolysates (e.g., HSP‑I) supported tightly regulated induction similar to tryptone, whereas carbohydrate-rich variants (e.g., HSP‑A) exhibited context-dependent “leaky expression.” Collectively, these findings support plant-derived peptones as consistent, scalable, and contamination‑resistant media supplements well suited for contemporary bioprocessing applications.