Scale-Up Challenges and Optimization Strategies for Green Fluorescent Protein Production in E. coli JM109: A Shake Flask and Batch Fermentation Study

Scale-up of recombinant protein production processes is a crucial step in biotechnology and involves the transition from small-scale shake flasks to large-scale bioreactors. This study aimed to detect errors and understand optimization strategies in the scale-up process of Green Fluorescent Protein (GFP) production using E. coli JM109 strain by comparing shake flask and batch fermentation approaches. Scale up process was inefficient (product yield efficiency was < 1). Shake flask cultures gave higher GFP production levels than the batch fermentation approach. The differences in GFP yield were attributed primarily to inconsistent KLa and OTR among other factors such as plasmid stability, cell density and scale-up parameters. Furthermore, the study investigated the impact of process parameters like wet cell weight, dry cell weight, and optical density on GFP productivity. It was observed that despite having a high cell density in the batch fermentation approach, the total protein yield in mg/mL was lower compared to the shake flask method values (200 F = 6.247, 250 F = 8.024, 200 SF = 9.948, 250 SF = 10.209). The influence of promoter regions on GFP expression and the potential benefits of protein engineering for enhancing protein production was also explored. The results underscores the importance of understanding and optimizing various factors during the scale-up process to ensure efficient GFP production and management of resources. By keeping OTR constant and addressing issues such as plasmid stability, lysis step, cell density, viability, scale-up parameters, and promoter activity, GFP yield can be improved in large-scale bioreactors. Additionally, protein engineering strategies could provide valuable tools for enhancing GFP expression and production, ultimately contributing to the development of more efficient protein production platforms in the biotechnology industry.