SUPPLIER SIDE

Mind the Gap

Managing Relationships Between
Upstream and Downstream Intensification
Priyanka Gupta and Katy McLaughlin

Process intensification (PI)describes an integrated
framework of strategies tomaximize the output of a unit
operation, a process, or an entire
facility. By implementing PI strategies,
biomanufacturers can accomplish theirproductivity goals by increasing
production speeds and titers, reducing
facility footprints, and cutting costs.
Overall, such changes improve
production efficiency and flexibility.
Collectively, the biotherapeuticindustry has made multiple
advancements in intensifying upstream
processing. PI strategies include using
high-density cell banks, implementing
seed-train intensification (n – 1perfusion), and incorporating theprinciples of continuous manufacturing(with concentrated fed-batch
production and dynamic perfusion
technologies). Such intensification
approaches deliver increased titers at
the end of upstream process steps.
However, manufacturers now reach apotential bottleneck in theirintensification journey: handling higher
masses and concentrations
downstream.

Downstream Process
Intensification Bottlenecks

To guarantee a smooth transition fromupstream to downstream process
steps and maximize the potential
benefits associated with PI,
biomanufacturers must optimize theirdownstream processes to handle thosehigher titers.
Uncharted Waters: A number of
established intensification schemes
38 BioProcess International20(3)adapt to needed changes? Are therequired modifications cost-effective?

Unlock Efficiency in Your
Downstream Process

work well across upstream
bioprocesses (Figure 1) (1). By contrast,
downstream PI processes andplatforms are less established and canrequire more work to develop andoptimize. However, thebiopharmaceutical industry isexperiencing a turning point, withadvancements in purification
technologies and intensification trends,
including evolving purification
strategies, a move toward single-use
manufacturing, and broadened
adoption of continuous processing.
Fractured Thinking: Implementing
up- and downstream PI strategies as
individual operations can result inapproaches that do not complement
one another. At worst, they can beantagonistic. Steps that intensify an
upstream process undoubtedly will
influence what must be accomplished
downstream. Compared with standardfed-batch processes, samples from anintensified upstream process are likely
to contain both higher product titers
and increased impurities when they
move downstream. A biomanufacturer
must assess whether its current
downstream scheme can handle
additional purification challenges. If
not, can the facility be modified toMarch 2022

To “mind the gap” between upstream
and downstream intensification, youneed to have detailed insights into therelationships between production
stages. When designing your overall
strategy for implementing PI, you
should consider adopting a stepwisemethod. Taking a gradual, linear
approach can minimize disruptions,
reduce development and optimization
timelines, and ensure that you cancapitalize on the potential benefits ofintensification.
Examine Your Existing Process:Before embarking on a PI journey,
review your current practices. You may
already have adopted someintensification principles: PI need not
be an all-or-nothing approach. The
broad spectrum of strategies under thePI umbrella includes small, incremental
changes to a standard fed-batchprocess, such as intensifying a seedtrain (1) or exploring continuous
manufacturing strategies (2).
Aim for Synergy: Production steps do
not function independently, so you
should consider the impact of upstream
PI on downstream procedures as soon
as possible. For each upstream change,
you should examine the effects ofincreased mass on your downstream
process. You should be able toanticipate what will come from theproduction bioreactor and prepare
accordingly — and you will probably
need to reoptimize your downstreamSponsoredsteps. That will require careful
communication and cooperation
between departments. In extreme
cases, you may need to explore entirely
new downstream approaches. For
example, increased cell densities
generated in a production bioreactor
might preclude current clarification
procedures from efficiently removing
the resulting cell mass. Perfusion/
continuous upstream processing
requires that you capture your productevery day — and ideally, purify it daily.
To take full advantage of the benefits of
PI upstream, you could implement
multicolumn chromatography (MCC),
thereby bridging the gap and extending
continuous processing strategies acrossthe entire process.
Take a Stepwise Approach: Once you
have an idea of operations that can beintensified, you can implement
additional intensification steps
gradually, starting with upstream andmoving into downstream operations.
Whether downstream steps require
adjustments as a consequence ofupstream PI depends on modality andproduction parameters. A step-by-step
strategy ensures that changes areapplied as smoothly as possible byconsidering independent short- andlong-term goals. Applying
intensification principles might requiresignificant changes to unit operations,equipment, and/or an entire facility.
Disruptions should be kept to aminimum to prevent costly delays,
which can be an especially criticalconsideration for small or new facilities.

An Integrated Approach toProcess Intensification

Applying PI principles can help
biomanufacturers satisfy key businessdrivers and remain strong in acompetitive and tightly regulated
market. However, developing a clear
integration strategy for upstream anddownstream intensification will enable
you to reap the rewards of PI.
In an ideal situation, bioprocessors
will consider the impacts of their
upstream intensification approaches
on downstream processes before
implementing changes. That provides
two related benefits. When consideredin the context of upstream production,
downstream process steps can be
SponsoredFigure 1: Upstream process-intensification (PI) schemes
Feed

1 Standard Fed-Batch

1Feed
2

Base

Antifoam

3 Concentrated
Fed-BatchMedia
1

2 n – 1 Perfusion

Feedor

1

Feed
2

Base

AntifoamMedia
1MediaWaste

4 Dynamic Perfusion

Constant
FlowControl
Clarified
Harvest1 The standard cell-culture technique used
across the biopharmaceutical industry is
fed-batch culture, in which cells arecultured in a bioreactor, typically for 14days. Protein harvest occurs only at theend of the fed batch. Feed media areadded gradually to replenish nutrients andgrowth factors during the process.
2 Seed-train intensification is one of thequickest and simplest ways to apply
process intentification to a new or existingprocess. In an n – 1 perfusion, highinoculum, fed-batch process, a productionbioreactor is seeded with a higher numberof cells, reducing the time needed to reachdesired cell densities for production or todeliver a higher titer within the same timescale as would a standard fed-batch
culture.

designed to ensure efficient productpurification for the titers and volumes
generated with PI. And after
intensifying upstream production, you
can apply similar principles todownstream processing, making yourentire production process continuous.
As one example, dynamic perfusion
culture can be followed by MCC.
Taking a stepwise approach to
implementing downstream processintensification and developing aroadmap with clear milestones will help
you to reap the rewards of your entire
PI journey.

References
1 Matuszczyk J-C, et al. Intensified
Seed Train Strategy for Faster, Cost-3 In concentrated fed-batch processes,production and feed media are refreshedcontinually in a perfusion bioreactor. Spentmedia pass through a retention device andgo to waste. Cells and protein products arerecirculated and returned to the bioreactor.
The media feed is continuous, but theprotein of interest is harvested only at theend of the culture.
4 In perfusion processes, media circulate
through a growing culture to supply
nutrients while waste is removed andproduct is harvested in a single operation.
The entire volume of medium is exchanged
daily while cells are retained and waste isminimized, thus increasing cell density,
culture longevity, and protein production.
Combined production and feed media areneeded to provide sufficient nutrients forhigh cell densities.

Effective Scale-Up of Biologics
Manufacturing. BioProcess Int. 18(11–12)
2020: 62–64; https://bioprocessintl.com/
sponsored-content/rm-perfusionbioreactors-intensified-seed-train-strategyfor-faster-cost-effective-scale-up-ofbiologics-manufacturing.
2 Mihal C. In With the New: Embracing
Multicolumn Chromatography. The
Medicine Maker (14 May 2021); https://themedicinemaker.com/manufacture/
in-with-the-new-embracing-multicolumnchromatography. cCorresponding author Priyanka Gupta is
the head of external collaborationsseparations technology atSartorius; priyanka.gupta@sartorius.com;
1-408-872-2442. Katy McLaughlin is ascientific content writer at Sartorius.

March 202220(3)BioProcess International39