Article | June 18, 2013Dr Sharon Williams, Product & Downstream Process Development Manager, ProMetic BioSciences Ltd
Escherichia coli is a Gram-negative bacteria that is a popular host organism for the expression of recombinant protein bio-therapeutics. Lysis of the outer membrane of Gram-negative bacteria, a requirement to release internalised target biomolecules, also releases substantial quantities of lipopolysaccharides (LPS – also known as endotoxin) into the process solution.
LPS elicits a variety of pathophysiological effects on the body and its removal to acceptable levels, particularly in the presence of proteins with which it often associates, continues to be a major challenge.
The currently accepted maximum endotoxin dose limit is 5 EU per kg body weight per hour. 1 EU is equivalent to 0.1 - 0.2 ng of endotoxin so purification processes need to be very effective in removing LPS from the product. Frequently there is reliance on established purification steps such as ion-exchange chromatography to remove endotoxin though separating LPS from proteins can be very challenging and is not always achievable by this approach.
Here we describe a novel, non-toxic and highly stable synthetic affinity adsorbent (EtoxiClear™) identified for the capture and removal of endotoxin from a wide range of biological products. EtoxiClear™ comprises a specific affinity ligand attached to near mono-disperse 6% cross-linked agarose bead (PuraBead ® 6XL) which is resistant to high pH and can be depyrogenated using NaOH.
https://www.bioresearchonline.com/Doc/a-novel-affinity-adsorbent-capture-removal-endotoxin-0001