Comparison Between Simple Batch and Fed-Batch Bioreactor Cultivation of Recombinant BCG

Author(s)

Mendes, Sarah ; Goncalves, Maria C. P. ; Aiex, Vitoria A. P. ; Batista, Ryhara D. ; Zorzete, Patricia ; Leite, Luciana C. C. ; Goncalves, Viviane M.

• Document type: Journal article
• Source: PHARMACEUTICS; v. 16, n. 11, p. 12-pg., 2024-11-01.

Abstract

Background/Objectives: Tuberculosis continues to be a significant global health concern, causing 1.3 million deaths in 2022, particularly affecting children under 5 years old. The Bacillus Calmette-Gu & eacute;rin (BCG) vaccine, developed in 1921, remains the primary defense against tuberculosis but requires modernized production methods. The recombinant BCG-pertussis strain shows potential in providing dual protection against tuberculosis and whooping cough, especially for vulnerable newborns, and enhanced efficacy against bladder cancer. Implementing submerged cultivation techniques for rBCG-pertussis production can offer increased productivity and standardization. Methods: This study explores a fed-batch cultivation strategy with pH-stat control to feed L-glutamic acid through the acid pump into 1 L bioreactor. Three pH values were evaluated for fed-batch and a simple batch without pH control was done for comparison. The viable cell concentration was compared before and after freeze-drying samples harvested during the cultures. Results: L-glutamic acid was identified as the preferred substrate for rBCG-pertussis. While the fed-batch strategy did not enhance the maximum specific growth rate compared to simple batch cultivation, it did improve the specific growth rate after day 4 in the pH 7.4-controlled fed-batch cultures, thereby reducing the cultivation time. Fed-batch cultures controlled at three pH levels exhibited lower optical density than the simple batch, although the viable cell counts were similar. Notably, samples harvested after day 8 from the simple batch cultures showed a reduction in CFU/mL after freeze-drying, whereas all fed-batch samples exhibited high recovery of viable cell counts post lyophilization. Conclusions: The additional glutamate supplied to the fed-batch cultures may have protected the cells during the lyophilization process. (AU)

• FAPESP's process: 22/15269-4 - Assessment of pH control and feeding of amino acid and carbon sources to optimize the onco-rBCG-pertussis immunotherapy production in 1 and 10 L bioreactors
• Grantee: Maria Carolina Pereira Gonçalves
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/24832-6 - Development of vaccines based on recombinant BCG: Tuberculosis, Pertussis, Pneumococcus and Schistosoma
• Grantee: Luciana Cezar de Cerqueira Leite
• Support Opportunities: Research Projects - Thematic Grants