Although Chinese hamster ovary (CHO) and Escherichia coli cells have become the biopharmaceutical industry’s preferred platforms for producing recombinant proteins, perennial challenges have limited the capabilities of those expression systems. New CHO lines and improved upstream methods steadily are increasing expression titers, yet researchers continue to decry CHO’s relatively low growth rate. E. coli exhibits strong growth kinetics but cannot perform posttranslational modifications necessary for complex therapeutic proteins. Researchers need advanced technologies and analytical methods to overcome such limitations. This…