Several recombinant protein based drugs, produced by various expression systems are approved by FDA.
Among prokaryotes, Escherichia coli has always been
preferred for production of recombinant proteins as it
offered several advantages including high growth rate,
simple media requirement, easy to handle, high yield
and very cost effective. However, there are some disadvantages
using E. coli expression system, such as loss
of plasmid and antibiotic property, unsolicited inducers
for gene expression, intracellular accumulation
of heterologous proteins as inclusion bodies, improper
protein refolding, lack of post- translational modifications
(including unable to form disulphide bonds),
protein-mediated metabolic burden and stress, endotoxin
contamination, poor secretion, proteolytic digestion and
complexity in downstream process [30-32].