We evaluated filtration behavior and virus removal capability for a monoclonal antibodies (mAb) and plasma IgG under constant flow rate directly following flow‐through column chromatography in an integrated process. mAb solution with quantified host cell protein (HCP) content processed in flow‐through mode on in‐series mixed‐mode AEX and modified CEX columns connected to the Planova BioEX filter (pool‐less) achieved HCP logarithmic reduction value (LRV) of 2.3 and 93.9% protein recovery, demonstrating comparable or higher HCP LRV with high protein recovery compared to previous reports. For 5–15 mg/ml plasma IgG run to 100 L/m2, similar filtration behavior was achieved for flux of 10–100 LMH, and lower flux runs remained well below the maximum operating pressure, suggesting that higher throughput in continuous processing is achievable. Comparison of fit of plasma IgG and mAb filtration behavior to four blocking models showed little differences but slightly better fit to the cake filtration model. Viral clearance of the filtration step tested by in‐line spiking X‐MuLV or MVM into purified plasma IgG following the chromatography step showed robust removal at low flux. Integrating the Planova BioEX filter into continuous processes with column chromatography can achieve efficient downstream processing with reduced footprint and process time.

An intimate relation between structure and mechanical properties of regenerated cellulose (Rayon, Benberg, etc.) has been investigated by measuring the humidity and temperature dependencies of infrared spectra, X-ray diffraction, and dynamic viscoelastic properties. At first the dynamic viscoelastic property and the infrared spectra were measured simultaneously during the increasing relative humidity at a constant rate (2% relative humidity/min) at room temperature. The Young's modulus was found to decrease remarkably around 40% relative humidity, where the content of the absorbed water increased largely as evaluated by the infrared spectral data. The water was considered to play a role as a plasticizer. Second, the temperature dependence of dynamic viscoelastic property was measured for the regenerated cellulose in a wide temperature region under the atmospheric environment. When the sample was heated from −150 °C, the anomalous phenomena could be observed in the temperature region of ca. −40 °C to room temperature:  the Young's modulus was diverged, and the intensity and peak position of the X-ray reflections were shifted and the infrared absorbance of the water molecule increased. When the liquid paraffin was pasted on the surface of the cellulose sample, such anomalous phenomena were not observed. The temperature region of these anomalous changes was found to correspond to the region where the absorbed water molecules changed the aggregation state drastically from solid ice to liquid water. In other words, the change in the aggregation state of the absorbed water is considered to affect the mechanical behavior of the regeneated cellulose quite seriously.

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