Abstract:
Despite the advantages of plant-based transient expression systems relative to
microbial or mammalian cell systems, the commercial production of recombinant proteins
using plants has not yet been achieved to any significant extent. One of the challenges has been
the lack of published data on the costs of manufacture for products other than
biopharmaceuticals. In this study, we report on the techno-economic analysis of the production
of a standard commercial enzyme, namely, horseradish peroxidase (HRP), using a transient
expression system in Nicotiana benthamiana. Based on the proven plant yield of 240 mg
HRP/kg biomass, a biomass productivity of 15-kg biomass/m2/year and a process yield of
54 % (mg HRP product/mg HRP in biomass), it is apparent that HRP can be manufactured
economically via transient expression in plants in a large-scale facility (>5 kg HRP/year). At
this level, the process is competitive versus the existing technology (extraction of the enzyme
from horseradish), and the product is of comparable or improved activity, containing only the
preferred isoenzyme C. Production scale, protein yield and biomass productivity are found to
be the most important determinants of overall viability.
