HYDROLYSATES AS SERUM REPLACEMENTS
Plant-based hydrolysates were one of the first nonanimal-derived supplements to replace serum and performed as a robust media
across a variety of cell lines and types. Known to provide amino acids, peptides, carbohydrates, vitamins, and minerals, hydrolysate
supplements have delivered growth rates and product titers comparable to serum or complex chemically defined media.
A recent study examined hydrolysate fractions to determine functionality. Interestingly, not only were hydrolysates found
to be an important source of free amino acids but also appeared to stimulate more efficient cell metabolism. In addition,
the oligonucleotide fraction was found to remain largely intact during culture conditions, suggesting a role other than as
nutrition, such as a possible protective role from shear stress or anti-apoptotic function to promote enhanced growth and
productivity.
This effect on cell metabolism has been observed for both hybridoma (Sp2/0) and Chinese hamster ovary cells (CHO) cultured
in chemically defined media (CDM) supplemented with plant-based hydrolysates. A metabolic shift was observed where the cultured
cells began to metabolize lactate as the carbon source once glucose and glutamine had almost been consumed. In addition, both
glucose and glutamine were consumed at a more rapid rate in supplemented cultures.
Figure 1: A metabolic shift occurred when Chinese hamster ovary (CHO) cells were cultured in chemically defined media plus
plant-based hydrolysate (HyPep 1510), resulting in increased cell density and productivity. (ALL FIGURES ARE COURTESY OF THE
AUTHOR)
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Accumulation of lactate during mammalian cell culture is a major concern because it can adversely affect cell growth and product
quality. The metabolic shift observed when CDM was supplemented with plant-based hydrolysates resulted in an extended growth
period and significant increase in product titer (see Figure 1).
NEW PLATFORM TO ADDRESS HYDROLYSATE DEFINITION AND VARIATION
Plant-derived protein hydrolysates have been shown to be an effective replacement for serum and animal-derived components,
delivering consistent benefits to cell performance parameters. Although the manufacture of these products is well controlled,
hydrolysates by their own nature are complex and not fully defined.
With the aim of streamlining biologic production processes and reducing costs, consistency and predictability are becoming
a major focus for the biotech industries. Acknowledging these trends, a new hydrolysate platform has been developed, which
maintains the animal-free requirements of the supplement while minimizing variability issues and delivering a more reproducible
product.
The production process is based on an innovative approach to enzymatic digestion involving a non-animal enzyme cocktail of
both proteases and nonproteolytic enzymes. The highly optimized process is designed to expand the range of nutritional factors
available to the cell, providing growth-promoting peptides as well as essential amino acids, carbohydrates, lipids, minerals,
and vitamins. Importantly, product consistency can be enhanced and interlot variability can be reduced because the process
requires fewer process steps.
Figure 2: Chinese hamster ovary (CHO) cell cultures supplemented with yeast hydrolysate maintained higher cell densities compared
with chemically defined medium (a) translating to an increase in product titer (b); YE is yeast extract; UFYE is ultrafiltered
yeast hydrolysate.
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Experimental data obtained from the comparison of CHO cells cultured in CDM alone to CDM supplemented with ultrafiltered yeast
extract (UFYE) demonstrated significant performance benefits in the supplemented cultures. Peak cell density was achieved
earlier in culture and was maintained for longer for UFYE when compared with the CDM control (see Figure 2a). The effect on
cell growth translated to a significant increase in product titer (see Figure 2b).
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