Like E. coli, they grow rapidly and are very
easy to handle and amenable to various genetic manipulations.
Recombinant proteins produced in yeast are
properly folded and glycosylated to a certain extent similar
to the one expressed in mammalian cells. Various human
therapeutic proteins, including therapeutic monoclonal
antibodies are being produced in mammalian cell lines
such as Chinese hamster ovary (CHO) and Baby hamster
kidney (BHK) cells. Recombinant proteins expressed in
mammalian cells are properly folded, glycosylated and
generally yield a functionally active protein [36]. However,
the production cost of biopharmaceuticals using mammalian
expression system is very high due to expensive culture
media. However, when we look at the number of
approved biopharmaceuticals by United States and/or the
European Union for 2013 recorded above average as compared
to past five years. The mean rate of approval is 13 as
shown in the Figure 2 [5-13]. Remarkably, the number is
same for both the years 2009 and 2013.