Barley grains for the production of endotoxin-free growth factors

• Plant platforms are emerging as a new and promising option for the production of recombinant proteins.
• Recombinant proteins can introduce endotoxin when added to a cell culture.
• Producing recombinant proteins in barley seed is a robust and well-established process.
• Barley seed is an ample platform for producing high quality, endotoxin-free proteins for use in medical research.

The most popular hosts for recombinant protein production have now in many cases passed their low-hanging-fruit era and their limitations as production hosts are becoming more evident. Therefore, the bioprocessing community is constantly on the lookout for new hosts that can complement the current selection. The development of plant systems is eagerly followed because of the great potential they show, such as much reduced production cost and absence of endotoxins and human pathogens. In this review, we describe the unique barley-based platform for recombinant protein production. We summarize the methods used for gene modification and protein processing and discuss the main advantages of the system. Finally, we discuss the significance of endotoxin-free proteins for cell-based research and therapeutic applications.