Downstream Development

Shrinking the Costs of Bioprocess Development

Process development for large-scale bioproduction is generally more labor-intensive, time-consuming, and expensive than for comparable nonbiological processes because of the large number of individual processes and potential variables involved. To ensure the future commercial viability of biological manufacturing processes and prevent bottlenecks, it is essential to accelerate development of both upstream and downstream processing, as well as to improve process analytics. This not only reduces time and cost factors involved in design of robust bioprocessing protocols, but also reduces the…

Creation of a Well Characterized Small Scale Model for High-Throughput Process Development

    Streamlining process development has been the focus of the biotechnology industry over the past several years. To be financially viable in the current market, a company has to be competitive in all three of the following areas: quality, speed, and price (1). Attaining any two of the three attributes at a time is no longer sufficient. With new tools and technologies along with improved understanding of the cell-culture process, doing high-quality process development while reducing both cycle time…

Investigating Flow Distribution and Its Effects on Scale-Up

Depth filtration is widely used in the biopharmaceutical industry to purify target proteins by removing whole cells, cellular debris, fines, aggregates, and colloidal particles from the fermentation broth (1,2). At large scale (>2,000 L), culture harvest from a bioreactor is typically processed with a disc-stack centrifuge to remove cells and cell debris. Although centrifugation is very effective for removing whole cells and larger debris, it cannot remove small-size particles, which remain suspended in the centrate. Depth filters are commonly used…

Setting the Stage

Much has already been written lately about addressing the so-called “downstream bottleneck(s).” A number of companies are leading the way toward developing products and platforms for reducing both the costs and the time required for downstream processing. Our task with this special issue was to provide a state-of-the-art update on these activities — but as always, within a limited number of pages allotted. The primary issue behind this bottleneck debacle is to address purification challenges posed by aggregation in cell…

Development of a High-Capacity MAb Capture Step Based on Cation-Exchange Chromatography

Protein A affinity chromatography is traditionally used as the capture step for monoclonal antibodies (MAbs) (1,2,3). It yields high purity because only the fragment-crystallizable (Fc) region of an antibody (IgG1 or IgG2) or Fc-containing fusion protein can bind to the protein A ligand. The resulting specificity provides substantial reduction in impurities such as host cell proteins (HCPs) and DNA (4,5,6,7,8). The dynamic binding capacity of protein A chromatography resins is generally ≤40 g/L and depends highly on residence time because…

Increasing MAb Capture Productivity

Continually increasing bioreactor titers is placing pressure on downstream processing, especially chromatography steps, to process the greater mass of protein produced. Whereas an order of magnitude increase has been seen in titers over the last few years, no similar increase has yet been achieved in the capacity of chromatography resins. Meanwhile, the industry is coming under rising pressure to reduce manufacturing costs and the resulting cost per gram of monoclonal antibodies (MAbs) produced. Because of the specificity it offers, protein…

Use of Membrane Technology in Bioprocessing Therapeutic Proteins from Inclusion Bodies of

The ultimate goal of recombinant fermentation research is cost-effective production of desired proteins by maximizing volumetric productivity (to obtain the highest amount of protein in a given volume in the least amount of time). Bioprocessing for recombinant proteins using genetically modified organisms requires a stable, high-yielding recombinant culture, a highly productive fermentation process, and cost-effective recovery and purification procedures. Escherichia coli has been a widely used host for expression of recombinant proteins (1). Its advantages lie in the enormous data…

Rapid Purification of Lys-C from Cultures

Endoproteases specific for cleavage of peptidyl bonds on the C-terminal side of lysine residues (e.g., Lys-C) are produced from a number of bacterial species, including Achromobacter lyticus (1), Pseudomonas aeruginosa (2), and Lysobacter enzymogenes (3). The Achromobacter protease 1 (API) protein has been substantially characterized (4,5,6) and shown to be a resilient enzyme that can specifically cleave after lysine residues under a wide range of buffer conditions, including high concentrations of denaturing agents such as urea and sodium dodecyl sulphate…

Purifying a Recalcitrant Therapeutic Recombinant Protein with a Mixed-Mode Chromatography Sorbent

Mixed-mode chromatography sorbents can save time and money by reducing the number of steps required to purify recombinant proteins. They also have the potential to purify proteins that single-mode sorbents cannot. As the term mixed mode suggests, these sorbents contain ligands that offer multiple modes of interaction. Although mixed-mode sorbents are used extensively in solid-phase extraction for high-pressure liquid chromatography (HPLC) sample preparation — and to a more limited extent in analytical HPLC — these resins are generally unsuitable for…

MAb Contaminant Removal with a Multimodal Anion Exchanger

Monoclonal antibodies (MAbs) constitute ∼30% of the biopharmaceutical products currently under development (1). An increasing demand for MAbs during the past decade has led to intense development of high-expression cell cultures (2). Today, it is possible to see titers of 4–5 g/L, and expression levels as high as 15 g/L and greater have been reported. As a consequence, demand has increased for more efficient downstream processes. That demand, combined with its potential for reducing time-to-market, has increased interest in the…