The rapid increase in the number of

The rapid increase in the number of diabetic patients globally and exploration of alternate insulin delivery methods
such as inhalation or oral route that rely on higher doses, is bound to escalate the demand for recombinant insulin
in near future. Current manufacturing technologies would be unable to meet the growing demand of affordable
insulin due to limitation in production capacity and high production cost. Manufacturing of therapeutic recombinant
proteins require an appropriate host organism with efficient machinery for posttranslational modifications and protein
refolding. Recombinant human insulin has been produced predominantly using E. coli and Saccharomyces cerevisiae for
therapeutic use in human. We would focus in this review, on various approaches that can be exploited to increase the
production of a biologically active insulin and its analogues in E. coli and yeast. Transgenic plants are also very attractive
expression system, which can be exploited to produce insulin in large quantities for therapeutic use in human.
Plant-based expression system hold tremendous potential for high-capacity production of insulin in very cost-effective
manner. Very high level of expression of biologically active proinsulin in seeds or leaves with long-term stability, offers a
low-cost technology for both injectable as well as oral delivery of proinsulin.