Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality, cell physiology, and IgG production in CHO cultures

Abstract

BACKGROUNDMany vital components in bioprocess media are prone to photo‐conversion or photo‐degradation upon exposure to ambient light, with severe negative consequences for biomass yield and overall productivity. However, there is only limited awareness of light irradiation as a potential risk factor when working in transparent glass bioreactors, storage vessels or disposable bag systems. The chemical complexity of most media renders a root‐cause analysis difficult. This study investigated in a novel, holistic approach how light‐induced changes in media composition relate to alterations in radical burden, cell physiology, morphology, and product formation in industrial Chinese hamster ovary (CHO) bioprocesses.RESULTSTwo media formulations from proprietary and commercial sources were tested in a pre‐hoc light exposure scenario prior to cultivation. Using fluorescence excitation/emission (EEM) matrix spectroscopy, a photo‐sensitization of riboflavin was identified as a likely cause for drastically decreased IgG titers (up to −80%) and specific growth rates (−50% to −90%). Up to three‐fold higher radical levels were observed in photo‐degraded medium. On the biological side, this resulted in significant changes in cell morphology and aberrations in the normal IgG biosynthesis/secretion pathway.CONCLUSIONThese findings clearly illustrate the underrated impact of room light after only short periods of exposure, occurring accidentally or knowingly during bioprocess development and scale‐ up. The detrimental effects, which may share a common mechanistic cause at the molecular level, correlate well with changes in spectroscopic properties. This offers new perspectives for online monitoring concepts, and improved detectability of such effects in future. © 2018 The Authors. Journal of Chemical Technology & Biotechnology published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

Construction of Z‐scheme Pt‐TiO2/(Er3+:Y3Al5O12@Ta2O5)/HAP and its application in sonocatalytic degradation of prometryn and disinfection of Escherichia coli

“…The peaks at 523 and 724 cm −1 are associated with the LO and transverse optical (TO) modes of Ta 2 O 5 , respectively. In fact, the peak centered at 1038 cm −1 is found, which is the υ1 symmetric stretching vibrations of the PO 4 3− . As depicted in Fig.…”

Towards robust cell culture processes — Unraveling the impact of media preparation by spectroscopic online monitoring

“…The 2D EEM matrix of the second supplier media batches had a decreased peak at ex450 nm/em530 nm when compared to the reference media (data not shown). This peak is known to be strongly influenced by riboflavin [5]. Finally, the riboflavin content of the reference media basal powder and the second supplier basal powder were analyzed and the results confirmed that the riboflavin content in the reference media was indeed significantly elevated in comparison to the second supplier basal powder.…”

“…Besides analytical and biological variability, a major source for variable process performances is often reported to be linked to the chemical media composition . Cell culture media often consist of more than 50 components, including substances with known stability issues such as cysteine, insulin, and riboflavin . Quality control for cell culture media may include raw material screening with spectroscopic methods as near‐infrared and mid‐infrared (MIR) spectroscopy .…”

“…Moreover, preparation parameters such as preparation time, temperature, and P/V can not be kept constant between all scales and preparation vessels but can strongly affect gas solubility/entry, powder dispersion, and chemical reaction kinetics . Although there is literature on the chemical degradation of cell culture media or impact of aged media on process performance available, to our knowledge there is no reported study investigating the effect of media preparation parameters on media quality. Therefore, the second study in this contribution focuses on the impact of variable media preparation parameters on cell culture media and subsequent fed‐batch processes using a design of experiments (DoE) approach.…”

“…Moreover, preparation parameters such as preparation time, temperature, and P/V can not be kept constant between all scales and preparation vessels but can strongly affect gas solubility/entry, powder dispersion, and chemical reaction kinetics [13,14]. Although there is literature on the chemical degradation of cell culture media or impact of aged media on process performance [2,5,6] available, to our knowledge there is no reported study investigating the effect of media preparation parameters…”