# Serum‐Free Japanese Encephalitis Virus Production in a Single‐Use Fixed‐Bed Bioreactor

## TL;DR

Researchers developed a serum-free method to produce Japanese encephalitis virus in a bioreactor, which could be more efficient and cost-effective than traditional methods.

## Contribution

The study introduces a serum-free JEV production process in a single-use fixed-bed bioreactor, offering scalable and cost-effective manufacturing.

## Key findings

- Serum-free media combinations significantly impact JEV yields in fixed-bed bioreactors.
- DMEM with high glucose content improved viral yields in serum-free conditions.
- Fixed-bed bioreactors showed comparable or better performance than roller bottles for JEV production.

## Abstract

Fixed‐bed bioreactors for anchorage‐dependent cells are an obvious choice for development because of their large‐scale capabilities, allowing manufacturing with reduced cost and footprint. In this study, a serum‐free production process for Japanese encephalitis virus (JEV) in a single‐use fixed‐bed bioreactor was developed and compared to conventional roller bottle production as a productivity benchmark. After optimization of serum‐free cell culture conditions, an initial media screening in roller bottles showed a strong impact of growth and production media on virus yields. Selected optimized medium combinations were assessed in roller bottles and the fixed‐bed bioreactor. Both systems proved to be excellent production systems for JEV, but media choice was key to achieve the highest titers. In particular, DMEM with its enriched glucose content beneficially affected viral yields, enabling potential large‐scale manufacturing using the fixed‐bed reactor with serum‐containing or serum‐free media.

Practical application: Data presented in this work show feasible ways of serum‐free virus production with Vero cells, a common cell substrate in vaccine development. The fixed‐bed bioreactor process described here could facilitate manufacturing activities to reduce cost and footprint while simultaneously achieving higher process control compared to conventional manufacturing systems like roller bottles. With a much better upscale potential (up to 500 m2) the fixed‐bed bioreactor showed comparable or better yields to roller bottles depending on media used, even with serum‐free media. This research article further emphasizes the need to optimize cell culture media or media combinations for each virus individually to achieve the highest titers. As shown, performing a simple media screening experiment to optimize yields early in process development could lead to better productivity, with a high business impact in later development stages.