Downstream Bioprocesses (I) Flashcards

This set of vocabulary flashcards covers the fundamentals of downstream bioprocessing, including primary recovery methods, filtration laws, and cell disruption techniques.

Downstream Bioprocessing (DSB)

The stage of a bioprocess where the bioproduct is recovered, extracted, concentrated, and purified (up to $\ge 99\%$) to meet specific quality and purity requirements.

Total Production Costs

The percentage of final manufacturing costs attributed to downstream processing, which can account for $> 85\%$ in many biomanufacturing processes.

Purity Requirements for Pharmaceuticals

The level of purity required for biologics and pharmaceuticals to ensure safety and efficacy, typically $\ge 99\%$.

Broth Conditioning

The preparation and treatment of fermentation broth before DSB to improve recovery efficiency, including step like pH adjustment, cooling, or the addition of protease inhibitors and DNAse.

Solid-Liquid Separation

The first step in downstream processing that removes cells, cell debris, or other particulate matter from the fermentation broth, also known as clarification.

Foam Flotation

A separation process where suspended solids attach to air bubbles and rise to the surface for removal by skimming, achieving high efficiency ($> 90\%$) with low energy consumption.

Centrifugation

A sedimentation technique using centrifugal force to separate mixture components based on mass or density.

Disk Stack Separator

A centrifuge featuring conical disks that uses high centrifugal force ($> 5,000\,g$) for continuous and efficient solid-liquid separation.

Tangential Flow Filtration (TFF)

A filtration method where the fluid flow is parallel to the membrane; the resulting shear force prevents clogging (fouling), making it highly scalable.

Darcy's Law

A formula describing volumetric flow rate through porous media: $Q = \frac{k \times A \times \Delta P}{\eta \times L}$, where $k$ is permeability, $A$ is area, $\Delta P$ is pressure drop, $\eta$ is viscosity, and $L$ is thickness.

Nanofiltration

A membrane filtration category where separation is based on both physical sieving and Donnan exclusion (charged membranes).

Reverse Osmosis

A high-pressure ($10-150\,\text{bar}$) filtration process where separation is based on solvent diffusion through a membrane.

Rotary Vacuum Drum Filter

A continuous filtration device consisting of a cylindrical membrane partly submerged in slurry, using internal vacuum to draw permeate through a filter cake.

Coagulation

A process step in wastewater treatment involving charge neutralization (often using multivalent cations) and rapid mixing to destabilize particles and form tiny pin-flocs.

Flocculation

The bridging step where long-chain anionic or non-ionic polymers link destabilized particles together into larger aggregates called flocs.

Cell Disruption (Homogenization)

An essential process for recovering intracellular products by opening or permeating the cell wall and membrane.

High-Pressure Homogenization

A mechanical cell lysis method where cell suspension is forced through a narrow orifice at ultra-high pressures ($600-2,000\,\text{bar}$).

Microbead Milling

A homogenization process using grinding beads agitated at high energy to lyse cells; it is effective for high-viscosity broths and contains no chemical contaminants.

Cell Milking (In Situ Extraction)

A bioprocess technique where valuable intracellular products are extracted from living microbial cells without killing them, often using two-phase extraction or osmotic shock.

Two-Phase Extraction

A cell milking method where a biocompatible solvent is added to the culture to fluidize the membrane and allow hydrophobic products to diffuse out.