Solid-Liquid Separation After Fermentation

Solid-Liquid Separation After Fermentation

As an important part of the overall fermentation process, downstream processing refers to separating and purifying products from the fermentation broth. It is worth mentioning that the solid-liquid separation process is a prerequisite to achieving the extraction of the target products.

BOC Sciences is a leading fermentation CDMO expertise in fermentation process development. With our extensive experience in the development of fermentation downstream processes, as well as advanced separation and purification technologies and supporting equipment, we are capable of providing solid-liquid separation services for fermentation broth processing.

Introduction of Solid-Liquid Separation

Solid-liquid separation is the first step of downstream processing after fermentation in order to separate whole cells (cell biomass) and insoluble components from the fermentation broth. If desired products are intracellular metabolites, they must be released from cell solutions before subjecting to the solid-liquid separation.

Fermentation broth processing refers to the recovery and purification of biosynthetic compounds from the fermentation broth. This process includes the recovery of recoverable components, as well as the appropriate treatment and disposal of waste as well. As a viable production technology, the fermentation process needs to be complemented by an optimized solid-liquid separation process.

Methods of Solid-Liquid Separation

  • Flotation: The use of collector substances allows stable foam formation in the fermentation broth. The introduction of gases into the fermentation broth results in the formation of bubbles that attach cells and solid particles, and then bubbles rise to a layer of foam that can be collected and removed.
  • Flocculation: In the fermentation industry, cells can form large aggregates and then settle, which can be collected and removed at the end of the fermentation process. The flocculation process depends on the nature of the cells and the ionic composition of the mediums, which usually requires the addition of flocculants such as inorganic salts, organic polyelectrolytes, and mineral hydrocolloids.
  • Filtration: The most common technique used to separate biomass from culture filtrate. The filtration efficiency depends on various factors, including the size of organisms, the presence of other organisms, the viscosity of mediums, and temperature. Currently, filtration technologies have made up a large sector of all industrial applications, such as depth filtration, absolute filtration, and membrane filtration.
  • Centrifugation: A method that is broadly adopted for the separation of particles or material according to various concentrations, applicable with cells, subcellular organelles, viruses, proteins, nucleic acids, and other large molecules. The centrifugation technique is based on the principle of density differences between the particles to be separated and mediums. In recent years, continuous flow centrifuges have facilitated large-scale industrial centrifugation.

Applications of Solid-Liquid Separation

Solid-liquid separation technologies for fermentation broth processing are widely used in chemical and pharmaceutical manufacturing, food processing, and other industries.

  • Separation of bacterial cells in the large-scale fermentation broth is an important process for producing bacterial vaccines.
  • Solid-liquid separation technologies, such as depth filtration and microfiltration, can be used to recover therapeutic proteins from high cell density fermentation on a commercial scale.
  • Certain microbial hosts expressing recombinant proteins lack the ability to secrete proteins into the culture medium, and centrifugation is used to remove cellular debris for protein recovery.

What Can We Do?

BOC Sciences is committed to providing one-stop fermentation CDMO services. Our services are highly flexible to meet individual clients’ needs, and our experienced experts will work closely with clients to effectively advance their projects towards commercialization.

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