Question

Using relevant examples, discuss the advantages and drawbacks of

protein expression in Escherichia coli and Pichia pistoris

Answer 1

Pichia expression system offers several advantages over other expression systems these includes:

- Suitable host for high expression with several post-translational modification,

- Grows easily with very high cell density in the defined medium, -

Easy scale up in large scale fermentation, and - Cost-effectiveness.

Its main limitation is its inability to produce postraductional modifications such as glycosylation.

The E. coli expression system allows rapid expression and subsequent large-scale, cost-effective manufacturing of recombinant proteins. This system is perfect for antigen expression and functional protein expression for non-glycosylated proteins.

One disadvantage of using an organism such as E. coli for expression of eukaryotic genes is that it is a prokaryote, and therefore lacks the membrane-bound nucleus (and other organelles) found in eukaryotic cells. This means that certain eukaryotic genes may not function in E. Coli.