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Bill Whitford
Bill Whitford
Strategic Solutions Leader
GE Healthcare Life Sciences
925 West 1800 South
Logan, Utah 84321
Mobile: +1 (435) 757-1022
Office: +1 (435) 792-8277
Fax: +1 (877) 434-4015

Bill Whitford is Strategic Solutions Leader, GE Healthcare in Logan, UT with over 20 years experience in biotechnology product and process development. He joined the company as an R&D Leader developing products supporting protein biological and vaccine production in mammalian and invertebrate cell lines. Products he has commercialized include defined hybridoma and perfusion cell culture media, fed-batch supplements and aqueous lipid dispersions. An invited lecturer at international conferences, Bill has published over 250 articles, book chapters and patents in the bioproduction arena. He now enjoys such activities as serving on the editorial advisory board for BioProcess International.

Development of Perfusion Culture Media for Continuous Biomanufacturing

It is generally understood that the development of platform-specific cell culture media is re-quired for economical, productive performance in biomanufacturing.  Heightened criteria for production media have driven suppliers to develop new high-efficiency, chemically defined and animal-product free basal formulations.  Despite the use of perfusion methods by some for many years, implicit in these products generally has been the intention that they would be employed in batch or fed-batch applications.  With some identified exceptions, this assump-tion included attached, suspension and microcarrier-based culture.  The increased popularity of perfusion culture has inspired suppliers to develop formulations specifically designed for perfusion applications.
Many commercial production media will support successful culture in most perfusion applica-tions, yet many unique challenges to optimal performance in perfusion application have been reported.  The first observation made by most operators is that the culture-medium volumetric productivity of a perfusion reactor at initial conditions is often lower than the that productivi-ty in fed-batch.  This has been demonstrated to be often due to the culture disproportionately demanding some sub-set of the formulation’s primary nutrients, and the reactors medium ex-change rate having been adjusted to maintain the supply those few components.  Secondly, as intensified perfusion culture determines such distinct operating conditions that the behavior/ characteristics of cells has been reported to often be quite different than in batch cul-ture.  Differences in the operating conditions include a much higher cell-density, equilibrium culture conditions (eliminating gradients of metabolite-to-cell ratios over time) and exposure to one of many medium exchange apparatus/technologies.
Each platform and clone can present a unique functional phenotype in this regard, yet some general observations have been noted.  They include a differential consumption rate between individual amino acids; a differential consumption rate between glucose and other primary metabolites; a reduction in the requirement for proteins or factors in the formulation; an altera-tion in the use of identified amino acids/glutamine and consequent lactate/ammonium genera-tion; differences in clumping potential; an increased or decreased demand for particular vita-mins; a new identified optimum in primary (feeding) osmolality; and a change in average size of the cells.  Also of note is that there are a few distinct styles of perfusion culture, each de-termining their own unique media design criteria.  For example, the ultra-high density, static culture environment of a hollow-fibre perfusion bioreactor (HFPB) presents concerns distinct from a wave-action based suspension culture perfusion reactor.  These include that sheer pro-tectants and antifoams are not required in HFPB and albumin secretion by hepatocytes grown in a HFPB was reported to be 15-fold higher than cells grown in traditional culture. Mode-specific secreted product residence time within a reactor, and its consequence, is another con-sideration.
Methods employed to develop perfusion media include blending of existing formulations, measurement of metabolite gradients during operation, concentration of unnecessary-component depleted formulations to reduce volumetric addition and custom-design of mini-perfusion apparatus to reduce cost and increase throughput in DoE directed experimenta-tion.  Finally, development of perfusion culture-specific media is occurring at a time when the importance of composition-determined post-translational properties (e.g. glycoform pattern) and in toto trace material contaminant (e.g., metals) effects is being revealed, complicating the endeavor.   Nevertheless, culture media manufacturers are now addressing perfusion-specific production formulations supporting the popular manufacturing platforms, perfusion types and product entities

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Key Dates
   Deadline for Submission of Abstract:
  October 31, 2018
   Notification of abstract acceptance:
   November 15, 2018