Much of the technology for batch adsorption of proteins and other biomolecules was originally developed for antibiotic purification from microbial fermentation sources. Both ion-exchange and hydrophobic adsorbents have been used for antibiotic purifications. Like other packed-bed applications, column adsorption is extremely susceptible to plugging by suspended insoluble materials in a feed-stream. Therefore, either efficient precolumn filtration or stirred tank adsorber configurations predominated.
In the late 1950s, Bartels et al. (22) developed the technology for sorption of the basic antibiotic streptomycin on cation exchange resins directly from fermentation broths in well-agitated tanks (actually in the form of upflow columns fitted with agitators to keep solids dispersed) without need for costly and loss-associated prefiltration. This breakthrough helped make adsorption processes competitive with traditional solvent extraction methods. Belter et al. published a similar anion exchange process to isolate the acidic antibiotic novobiocin in a series of specially designed, well-mixed columns with screens to pass mycelia but retain the resin (23). Periodically, the lead column was removed from the train, washed free of insolubles, and eluted in fixed-bed mode. Periodic countercurrent operation was obtained in the sorption sequence by advancing each of the uneluted columns one position and placing a freshly eluted column in the trail position of the train.
Modifications to surface chemistry of nonpolar adsorbent resins such as XAD-2 allowed specific capture of known fermentation by-products, such as removal of de-sacetylcephalosporin C from cephalosporin C, to produce a more potent antibiotic (24).
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