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Protein-based biopharmaceuticals require high purity before final formulation to ensure product safety, making process development time consuming. Implementation of computational approaches at the initial stages of process development offers a significant reduction in development efforts. By preselecting process conditions, experimental screening can be limited to only a subset. One such computational selection approach is the application of Quantitative Structure Property Relationship (QSPR) models that describe the properties exploited during purification. This work presents a novel open-source Python tool capable of extracting a range of features from protein 3D models on a local computer allowing total transparency of the calculations. As open-source tool, it also impacts initial investments in constructing a QSPR workflow for protein property prediction for third parties, making it widely applicable within the field of bioprocess development. The focus of current calculated molecular features is projection onto the protein surface by constructing surface grid representations. Linear regression models were trained with the calculated features to predict chromatographic retention times/volumes. Model validation shows a high accuracy for anion and cation exchange chromatography data (cross-validated R 2 of 0.87 and 0.95). Hence, these models demonstrate the potential of the use of QSPR to accelerate process design., (© 2024 The Authors. Biotechnology Journal published by Wiley-VCH GmbH.)

Mass-spectrometry-based proteomics is increasingly employed to monitor purification processes or to detect critical host cell proteins in the final drug substance. This approach is inherently unbiased and can be used to identify individual host cell proteins without prior knowledge. In process development for the purification of new biopharmaceuticals, such as protein subunit vaccines, a broader knowledge of the host cell proteome could promote a more rational process design. Proteomics can establish qualitative and quantitative information on the complete host cell proteome before purification (i.e., protein abundances and physicochemical properties). Such information allows for a more rational design of the purification strategy and accelerates purification process development. In this study, we present an extensive proteomic characterisation of two E. coli host cell strains widely employed in academia and industry to produce therapeutic proteins, BLR and HMS174. The established database contains the observed abundance of each identified protein, information relating to their hydrophobicity, the isoelectric point, molecular weight, and toxicity. These physicochemical properties were plotted on proteome property maps to showcase the selection of suitable purification strategies. Furthermore, sequence alignment allowed integration of subunit information and occurrences of post-translational modifications from the well-studied E. coli K12 strain., (© 2023 The Authors. Biotechnology Journal published by Wiley-VCH GmbH.)

A major challenge in the transition to continuous biomanufacturing is the lack of process analytical technology (PAT) tools which are able to collect real-time information on the process and elicit a response to facilitate control. One of the critical quality attributes (CQAs) of interest during monoclonal antibodies production is aggregate formation. The development of a real-time PAT tool to monitor aggregate formation is then crucial to have immediate feedback and process control. Miniaturized sensors placed after each unit operation can be a powerful solution to speed up an analytical measurement due to their characteristic short reaction time. In this work, a micromixer structure capable of mixing two streams is presented, to be employed in the detection of mAb aggregates using fluorescent dyes. Computational fluid dynamics (CFD) simulations were used to compare the mixing performance of a series of the proposed designs. A final design of a zigzag microchannel with 45° angle was reached and this structure was subsequently fabricated and experimentally validated with colour dyes and, later, with a FITC-IgG molecule. The designed zigzag micromixer presents a mixing index of around 90%, obtained in less than 30 seconds. Therefore, a micromixer channel capable of a fast and efficient mixing is hereby demonstrated, to be used as a real-time PAT tool for a fluorescence based detection of protein aggregation., (© 2022 The Authors. Biotechnology Journal published by Wiley-VCH GmbH.)

While packed bed chromatography, known as conventional chromatography, has been serving the biopharmaceutical industry for decades as the bioseparation method of choice, alternative approaches are likely to take an increasing leading role in the next few years. The high number of new biological drugs under development, and the need to make biopharmaceuticals widely accessible, has been driving the academia and industry in the quest of anything but conventional chromatography approaches. In this perspective paper, these alternative approaches are discussed in view of current and future challenges in the downstream processing field., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this study, an integrated approach involving the combined use of high-throughput screening (HTS) and column modeling during process development was applied to an industrial case involving the evaluation of four anion-exchange chromatography (AEX) resins and four hydrophobic interaction chromatography (HIC) resins for the separation of whey proteins having close pIs. From the HTS data, one resin of each type was selected (Capto Q and Octyl Sepharose 4 FF). Next, batch uptake experiments were performed to determine the adsorption isotherms of the major whey proteins on the selected resins, followed by isotherm parameters regression. Using the obtained isotherm parameters, the candidate chromatographic operations were modeled and experimentally validated. Finally, these were model-optimized and evaluated based on their optimized performances. In this example, Capto Q performed much better than Octyl Sepharose 4 FF in terms of column capacity, loading, throughput and productivity; hence, Capto Q was selected as the resin of choice for whey proteins separation. This operation was further scaled up from the lab scale (1 mL) to a preparative scale (35 L), with reproducible column elution profile. By this approach, a much wider space of operating variables could be investigated, thereby increasing the chances of finding the ideal operating conditions while keeping experimentation to the minimum., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The use of high-throughput screening (HTS) has been successfully applied over the past years in downstream process development of therapeutic proteins. Different HTS applications have been introduced to speed up the development of purification processes for these proteins. In the light of these findings, studies were conducted to develop a controlled method of pipetting the right amount of resin into self-packed filter plates. In total, 13 plates were tested for their suitability in an HTS application. Based on these studies, the Seahorse plate was experimentally verified as the best filter plate. Suitable conditions for preparing a self-packed plate were established so that linear correlations between resin concentration (POROS 50HS) and UV adsorption (420 nm) were obtained. The accuracy of dispensing the slurry into a microtiter plate was controlled within 1% deviation under established conditions. Overall, self-packed filter plates are equipped to be used in the development of purification processes in HTS mode., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This paper reviews the basic principles of the recently developed self-interaction chromatography (SIC) technique with regard to protein solution stability and protein crystallization. It gives experimental protocols for both normal-scale and micro-scale SIC experiments and reviews recent developments and current applications of this novel technique in the biopharmaceutical area. This paper aims to be a benchmark in the further proliferation of this highly effective and fast technology for the rational design of stable aqueous formulations of therapeutic proteins and the determination of solution conditions favoring protein crystallization.

The overexpression of recombinant proteins in Escherichia coli leads in most cases to their accumulation in the form of insoluble aggregates referred to as inclusion bodies (IBs). To obtain an active product, the IBs must be solubilized and thereafter the soluble monomeric protein needs to be refolded. In this work we studied the solubilization behavior of a model-protein expressed as IBs at high protein concentrations, using a statistically designed experiment to determine which of the process parameters, or their interaction, have the greatest impact on the amount of soluble protein and the fraction of soluble monomer. The experimental methodology employed pointed out an optimum balance between maximum protein solubility and minimum fraction of soluble aggregates. The optimized conditions solubilized the IBs without the formation of insoluble aggregates; moreover, the fraction of soluble monomer was approximately 75% while the fraction of soluble aggregates was approximately 5%. Overall this approach guarantees a better use of the solubilization reagents, which brings an economical and technical benefit, at both large and lab scale and may be broadly applicable for the production of recombinant proteins.