Microalgae as Bioreactors for Production of Pharmaceutical Proteins

Abstract

Eukaryotic microalgae have recently received significant attention as bioreactors for the production of recombinant pharmaceutical proteins, because of their simple growth requirements, ease of manipulation, and high growth rate. The unicellular green alga Chlamydomonas reinhardtii appears particularly valuable as a potential bioreactor since high levels of foreign protein accumulation have been achieved in its chloroplast. Apart from being easily transformed with foreign DNA, stable transgenic strains and high production volumes in full containment can be obtained with C. reinhardtii within a relatively short time. Furthermore, C. reinhardtii is a green alga that is generally recognized as safe for use as a food ingredient and therefore has the potential as a carrier for direct oral delivery of therapeutic proteins. In this article, we first summarize the recent progress on the use of transformed C. reinhardtii chloroplasts for molecular farming of therapeutic proteins and then discuss the technologies and strategies developed to increase the accumulation of recombinant proteins in this alga’s chloroplast. We show that transformed C. reinhardtii chloroplasts are a potentially robust bioreactor with the capacity to rapidly generate large quantities of high-value functional proteins at low cost.