Media‐dependent performance of rabies virus‐like particle production under low oxygen tension in baculovirus‐infected Sf9 cells

Abstract BACKGROUND Rabies continues to pose a major public health threat, causing approximately 59 000 deaths each year, especially in regions with limited resources where high costs restrict vaccine access. Safer and scalable vaccine platforms, such as virus‐like particles, are promising alternatives, but their production is highly sensitive to upstream process conditions. This study aimed to evaluate the impact of different culture media, a chemically defined medium (EX‐CELL® CD) and a serum‐free standard insect cell culture medium (Sf‐900™ III), on the production of rabies virus‐like particles using a baculovirus–Sf9 insect cell system in a bench‐scale bioreactor operated at low oxygen tension (10% air saturation). RESULTS EX‐CELL® CD supported superior cell growth (μ max = 0.037 vs. 0.019 1/h), higher rabies proteins volumetric yield (0.026 g L −1 vs. 0.021 g L −1 ), and increased productivity (0.206 vs. 0.183 mg L h −1 ). Transmission electron microscopy revealed statistically larger VLP in EX‐CELL® CD (59.7 ± 15.1 nm) compared to Sf‐900™ III (47.6 ± 16.2 nm), with statistical significance ( P ‐value = 0.021). CONCLUSION The use of the assessed chemically defined medium enhances both the efficiency and physicochemical properties of rabies virus‐like particle production, which are linked to stronger immune responses. These findings support the development of cost‐effective and scalable rabies vaccines, which could potentially improve access and impact in resource‐limited settings. © 2026 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).