(188ag) Yeast Hydrolysate Fractions and the Impact on Monoclonal Antibody Production

Cell culture media is one of the main focuses in upstream process development when assessing the cell culture performance of Chinese Hamster Ovary (CHO) cells for biologics manufacture. Yeast hydrolysate, a complex mixture that contains an undefined amount of peptides, vitamins, trace elements, carbohydrates, amino acids, etc, is historically used in CHO cell culture processes and has been shown to improve cell growth and productivity. Due to the complexity of its makeup, there is a high risk of lot-to-lot variability in yeast hydrolysate, which can impact consistency in cell culture performance. Development of an alternate, chemically-defined (CD) feed can mitigate this variability in production processes and improve consistency of biologics product quality and yield.

We implemented a systematic approach to identify components in yeast hydrolysate with the goal of identifying components that contribute the most to cell culture performance. Crude yeast hydrolysate was first separated by ultrafiltration into permeate and retentate fractions (Fractionation 1), using a 3kDa MWCO filter. Screening of Fractionation 1 in cell culture suggests that yeast hydrolysate components < 3kDa improve titer by 10% while maintaining similar cell growth. Through transcriptomics studies, we further characterized the production host’s response to yeast hydrolysate and Fractionation 1 to gain a better understanding of how these fractions impact CHO cell metabolism and monoclonal antibody production. In parallel, reverse phase HPLC (RP-HPLC) was used to further separate Fractionation 1 of < 3kDa through multiple rounds of fractionation. The latest fraction retains 6.8% of the original hydrolysate content while improving titer by > 15%. Further screening by mass spectrometry provided peptide profiling of these fractions, which will aid our efforts towards developing a CD “hydrolysate” feed inclusive of peptides that provide the highest metabolic potential to CHO cells.