Host systems for the production of recombinant spider silk

Spider silk is renowned for its impressive mechanical properties. It is one of the strongest known biomaterials, and the tensile strength of dragline silk outmatches both steel and Kevlar. However, the farming of spiders for their silk is unfeasible. Consequently, production of recombinant spider silk proteins (spidroins) in more amenable hosts is an exciting field of research. For large-scale production to be viable, a heterologous silk production system that is both highly efficient and cost effective is essential. Genes encoding recombinant spidroin have been expressed in bacterial, yeast, insect and mammalian cells, in addition to many other platforms. This review discusses the recent advances in exploiting an increasingly diverse range of host platforms in the heterologous production of recombinant spidroins.