The presence of either LucraTone Soy P or Soy F hydrolysate in CHO cell culture media improved cell densities and protein production by approximately 40–50%, compared to a media-only control. These levels were observed whether or not the hydrolysates had been ultrafiltered. The differences in specific protein production among the different experimental groups was negligible (data not shown), suggesting that the observed increase in protein production in CHO cells was the result of the hydrolysate facilitating higher cell densities rather than increased protein production per cell.
The addition of either UF or non-UF soy hydrolysate to the CD-CHO media increased CHO cell proliferation independent of the method of ultrafiltration (i.e., normal flow versus tangential flow). Both the UF and non-UF conditions performed comparably among the five lots that were tested with respect to cell densities, viabilities, and protein production.
This observation supports not only that the hydrolysates had low lot-to-lot variability, but also that the method of ultrafiltration did not impact hydrolysate performance. In addition, low endotoxin levels were detected in all hydrolysate samples that were used for testing, suggesting that ultrafiltration is not necessary as an endotoxin risk-mitigating activity. It should be noted that only LucraTone hydrolysates were tested, thus these results cannot be extended to hydrolysates produced by other manufacturers without further testing.
In summary, this study suggests that ultrafiltration of LucraTone Soy P hydrolysate has no impact on CHO cell culture growth or performance, nor is it required to deliver consistently low endotoxin levels. Our results provide scientific evidence to contradict the popular assertion that hydrolysate ultrafiltration improves cell culture performance.