Centrifuges serve as the cornerstone of downstream biopharmaceutical manufacturing processes. Leveraging centrifugal force, these equipment effectively separate biomaterials according to density to clarify process liquors and harvest cells. Ranging from cell culture harvest to lysate clarification and target product recovery, centrifugation plays a vital role in the production of high-purity biopharmaceuticals.
Modern biopharmaceutical centrifuges are generally operated in continuous mode to process large volumes (thousands of liters) of fermentation or cell culture broths while maintaining sterility and product quality. Disc stack centrifuges deployed in biotech manufacturing facilities accelerate the separation of cells and solid particulates from liquid culture media.
Each application scenario presents unique biological backgrounds and technical considerations. The following sections elaborate on the implementation of centrifugation, prevailing challenges, and suitable centrifuge configurations for respective processes.
Separation of CHO Mammalian Cell Cultures
Chinese Hamster Ovary (CHO) cells are the workhorse of biopharmaceutical manufacturing, widely adopted for the production of monoclonal antibodies and other therapeutic proteins. Upon reaching the harvest stage in fed-batch or perfusion culture, cells must be separated from the valuable extracellular target products contained within the culture supernatant.
Centrifugation acts as the primary cell harvesting method for this process. High-speed continuous disc stack centrifuges are commonly utilised to clarify cell culture broths, removing CHO cells and cell debris while retaining target proteins in the clarified supernatant.
Key technical considerations for CHO cell centrifugation include the relatively large cell size (~10–20 µm) and shear sensitivity of mammalian cells. Centrifuges need to deliver sufficient separation factor to sediment and capture cells (typically 5,000–10,000+ g), yet avoid excessive shear force that may trigger cell lysis and release impurities. Temperature control is also critical.
Harvesting is normally performed at low temperatures (4–10 °C) to preserve protein stability and inhibit microbial proliferation. Biopharmaceutical-grade disc stack centrifuges meet these requirements through closed, aseptic operation equipped with CIP/SIP (Clean-in-Place / Steam-in-Place) capabilities. Features such as automatic intermittent solids discharge are integrated to handle cellular biomass.
Clarification of Escherichia coli Lysate
Escherichia coli is a widely employed microbial host for manufacturing recombinant proteins including insulin, enzymes and plasmid DNA. Post-fermentation, bacterial cells are subjected to lysis (e.g., via high-pressure homogenisation) to release intracellular or periplasmic target products.
The resulting cell lysate contains cell debris, soluble proteins, DNA and other impurities. Centrifugal clarification constitutes a critical step to separate solid cell debris from the product-containing liquid phase. High-speed centrifuges rapidly remove massive debris and substantially reduce the load on downstream filters. For large-scale processes, continuous disc stack centrifuges with self-cleaning (solids ejection) bowls are preferred to handle lysates with high solids content and viscosity.
Steam-sterilisable disc stack centrifuges are purpose-built for such biotech applications, with processing capacities ranging from 100 to 10,000 L/h depending on E. coli feedstock characteristics. These centrifuges operate at high g-force to efficiently sediment fine bacterial debris.
Major technical challenges for bacterial lysate clarification stem from the small particle size of E. coli debris (typically <1 µm) and potential viscosity elevation induced by released DNA. Benefiting from the conical disc stack, disc stack centrifuges offer a large equivalent filtration area, yet may not remove ultra-fine particles below approximately 0.5–1 µm. Accordingly, centrifuges achieve primary clarification, followed by depth filtration of supernatant for further polishing to eliminate fine particulates.
Temperature control remains essential; lysate clarification is commonly conducted at 4 °C to stabilise proteins and mitigate foaming. For high-cell-density cultures, nozzle-type disc stack centrifuges can be adopted, which continuously discharge concentrated solids via peripheral nozzles to cope with heavy solids loading without frequent shutdowns. Centrifuges configured in this manner enable stable and scalable processing of E. coli lysates.
Separation of Saccharomyces cerevisiae
Saccharomyces cerevisiae, or baker’s yeast, is utilised not only in brewing and baking but also in biotechnology for vaccine production (e.g., hepatitis B vaccine) and recombinant protein manufacturing. In bioprocesses involving yeast fermentation, centrifuges are deployed to separate yeast cells from culture media. Yeast cells are larger (5–10 µm) and more robust than mammalian cells, rendering them generally easier to sediment.
The brewing industry heavily relies on disc stack centrifuges for rapid yeast removal and post-fermentation wort clarification. Similarly, within biopharmaceutical manufacturing, centrifuges collect yeast biomass for cell recovery or clarify supernatant when target products are extracellular. Centrifugal separation of yeast must account for high cell density and frequent viscosity elevation in fermentation broths.
Self-cleaning disc stack centrifuges deliver outstanding performance, capable of continuously processing large liquid volumes and periodically discharging dense yeast solids. Industrial yeast separators achieve throughput up to tens of thousands of liters per hour. Yeast exhibits lower shear sensitivity than animal cells, though gentle processing is still recommended if cell viability preservation is required.
In certain scenarios, decanter centrifuges are also applied for yeast separation, especially for dewatering high-solids slurries. Decanter centrifuges excel at producing concentrated yeast paste, whereas disc stack centrifuges are superior for generating clear liquid effluents. Nevertheless, disc stack centrifuges remain the preferred option for most upstream fermentation harvests owing to superior clarification performance and continuous operability.
Harvesting of Probiotics via Centrifugation
Probiotics such as Lactobacillus and Bifidobacterium are cultivated on an industrial scale for dietary supplements and functional food production. After reaching the target cell density, probiotic cells need to be harvested from fermentation media, followed by concentration and drying into powder formulations.
Centrifugation represents a mainstream technique to separate and collect probiotic biomass from culture media. Compared with filtration, centrifugation offers faster separation speed and higher efficiency, and functions as a closed, hygienic process well suited for large-scale production.
Continuous centrifugation enables uninterrupted probiotic harvesting directly from production fermenters. Several technical parameters must be addressed during collection. Cell viability is of paramount importance, as these bacteria must remain active upon administration to end consumers.
Therefore, separation processes should minimise cellular damage: gentle acceleration, prevention of overheating and short residence time inside centrifuges all help retain viability. Numerous industrial probiotic processes adopt disc stack centrifuges, which enable rapid cell separation within a sealed environment to avoid contamination. The large sedimentation area of disc stack centrifuges delivers satisfactory separation efficiency even for relatively small bacterial cells. Operations are generally maintained at cooled temperatures (<10 °C) to stabilise probiotic strains.
Post-centrifugation, concentrated probiotic cell paste undergoes further processing including washing, re-suspension, and subsequent freeze-drying or spray-drying. Disc stack separators have been widely adopted across the probiotic industry, demonstrating consistent reliability.
Feedstock enters through a central pipe and flows through numerous narrow disc gaps. Solid probiotic cells migrate outwards and are captured, while clarified effluent overflows for discharge. This design dramatically expands the effective sedimentation area and shortens sedimentation distance, achieving superior separation performance. By deploying this centrifuge technology, manufacturers can efficiently produce high-potency probiotic products. The proven performance and reliability of centrifuges in probiotic manufacturing plants have earned wide industry recognition, establishing centrifugation as the preferred separation solution for probiotic recovery.
Clarification of Chicken Embryo Allantoic Fluid (Vaccine Manufacturing)
Egg-based vaccine production (e.g., influenza vaccine) involves inoculating fertilised eggs with viruses, which replicate within the embryonic allantoic fluid. After incubation, virus-rich allantoic fluid is extracted from eggs.
Crude harvest contains target virions alongside egg proteins, cell debris and other impurities. Centrifugation is traditionally adopted for primary clarification of allantoic fluid to remove unwanted solids and coarse debris.
Continuous disc stack centrifuges operated at moderate rotational speed are typically deployed to separate cell debris, shell fragments and other particulates, yielding clarified virus-containing supernatant. The clarified allantoic fluid then undergoes further filtration and downstream processing such as ultrafiltration and chromatography for vaccine antigen purification.
One primary challenge for allantoic fluid clarification is processing heterogeneous solid mixtures while maintaining aseptic conditions. Feedstock may contain fine feather residues, shell particles and even semi-solid clots, which easily cause blockage if filtration is used alone. Centrifuges perform excellently in this regard by efficiently separating these solids. Given stringent sterility and closed-system requirements for vaccine manufacturing, centrifugal systems must be fully sealed and steam-sterilisable.
Centrifuges for allantoic fluid processing are commonly equipped with foam-free discharge systems (e.g., centrifugal pumps) to gently transfer clarified virus-containing liquid without foaming or shear-induced damage. Utilising such clarification centrifuges customised for vaccine harvest, manufacturers can process allantoic fluid harvested from thousands of eggs at high throughput while ensuring consistent clarity and product yield.
Plasma Separation in Blood Processing
Plasma serves as the starting raw material for numerous therapeutic products, including immunoglobulins, albumin, coagulation factor concentrates and other plasma-derived medicines. In blood banks and plasma fractionation facilities, centrifuges are extensively used to separate plasma from cellular components of whole blood.
When whole blood is centrifuged, stratification occurs: dense red blood cells settle at the bottom, a thin buffy coat consisting of leukocytes and platelets forms the intermediate layer, and straw-coloured plasma occupies the uppermost layer.
Industrial-scale plasma collection can employ batch centrifugation or continuous-flow apheresis centrifuges to process large volumes of blood. Rising demand for plasma-derived therapeutics has driven the need for high-efficiency centrifugal equipment to maximise yield and purity.
In practice, centrifuges must reliably separate plasma while minimising haemolysis and cross-contamination. Core considerations for plasma separation include gentle handling to avoid red blood cell rupture and cold chain preservation (plasma is normally stored at low temperatures to protect labile proteins). Continuous centrifugal systems applied in plasmapheresis operate at controlled speeds to continuously extract plasma and return red blood cells to donors.
Within manufacturing facilities, after pooled plasma is thawed, centrifuges can be utilised again to isolate precipitated proteins (e.g., cryoprecipitate enriched with Factor VIII). Centrifuges for blood and plasma processing are specialised disc stack or chamber centrifuges engineered for biosafety and aseptic operation, often fitted with single-use tubing or closed insert modules to eliminate cross-batch risks of blood-borne contamination.
The biopharmaceutical centrifuge portfolio also covers solutions for blood product processing. CIP-capable disc stack centrifuges support plasma centrifugation and other blood product applications, enabling efficient plasma separation in compliance with rigorous regulatory standards.
Harvesting of Peptide Crystals
Certain biopharmaceutical processes incorporate crystallisation steps for product purification or formulation. Representative examples include crystallisation of insulin (a peptide hormone) and other peptide or protein pharmaceuticals to achieve high purity and stability.
After crystal formation in solution, solid crystals must be separated from mother liquor and collected for drying. Centrifugation is commonly applied to separate crystalline solids from liquid phases in such crystallisation workflows.
Pharmaceutical manufacturing traditionally adopts batch vertical basket centrifuges or peeler centrifuges for this purpose, which remove liquid through rotation and mechanically discharge crystal cakes. For instance, batch centrifuges can harvest insulin crystals, facilitate in-bowl washing, and deliver materials for subsequent drying.
In other scenarios, decanter centrifuges are adopted for continuous crystal separation, particularly for continuous crystallisation processes. Equipment selection depends on production scale and crystal properties.
Technical factors governing peptide crystal centrifugation include crystal particle size (determining the choice between filtration and centrifugation), washing requirements to remove residual mother liquor or solvent from crystals, and temperature control (some crystals require low-temperature conditions to prevent dissolution or degradation).
Advantages of centrifugal separation include closed operation that reduces product exposure to ambient environment, and faster processing speed for large-volume feeds compared with gravity filtration. Notably, biopharmaceutical crystallisation generates highly concentrated products, and centrifuges are capable of handling thick crystalline slurries.
Conclusion
Centrifuge technology has demonstrated irreplaceable value across biopharmaceutical manufacturing. Capable of continuous and high-efficiency operation, centrifuges can replace or supplement filtration in numerous scenarios to better handle biomass and solid particulates. Equally importantly, biopharmaceutical separators are designed with full consideration of pharmaceutical operating environments, featuring integrated functions including CIP/SIP sanitation control, automated operation to ensure consistent process performance, and fully enclosed construction to guarantee biosafety.
