Anion Exchange Chromatography (GFP Purification part 2 of 6)

Anion Exchange Chromatography (GFP Purification part 2 of 6)


The Purification process begins as the transfer
tank of clarified lysate from the Recovery process is connected to the inlet pump on
the Chromatography skid. The first Chromatography step in our GFP purification
process is Anion-Exchange. At this point in the process, the pH of the clarified lysate
is about eight-point-zero, which means that the protein is negatively charged. Because
it is negatively charged, GFP will bind to the positively charged anion exchange resin. The pump draws the lysate from the vessel…past
the first conductivity sensor and pressure sensor…and through the zero-point-four-five
micron pre-filter. The pre-filter removes any residual cell debris or other particulates
that may have contaminated the solution. If the pre-filter begins to clog, the pressure
sensor at the inlet side of the filter will register a rising pressure…and the controller
will signal the need for a filter change. After pre-filtering and before the column,
the lysate passes through a flow meter… and an air sensor. Then, as the lysate passes
over the resin beads, the negatively charged protein attaches to the positively charged
beads. The solution leaving the column passes a UV
optical density sensor, a conductivity sensor and a pH sensor. The optical density sensor’s
low readings confirm that the GFP is not in the solution, so the outlet valve sends the
solution to waste.

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