Supplying materials on future NASA space missions could be a task assigned to bacteria Engineered bacteria produce spider silk proteins that can be spun into strong fibers (top; higher magnification cross-section view on bottom). Source: Christopher Bowenengineered to synthesize spider silk and other proteins. The bio-engineering approach pioneered by researchers from Washington University St. Louis yields spider silk for mechanically demanding extraterrestrial and Earth-bound applications without requiring the actual presence of spiders.

The materials production system presented at the American Chemical Society Spring 2019 National Meeting & Exposition uses bacteria-based platforms for in situ resource utilization. The long, repetitive DNA sequences responsible for spider silk protein production were shortened for insertion into bacteria, simplifying the synthesis process for these organisms.

Supplying materials on future NASA space missions could be a task assigned to bacteria Engineered bacteria produce spider silk proteins that can be spun into strong fibers (top; higher magnification cross-section view on bottom). Source: Christopher Bowenengineered to synthesize spider silk and other proteins. Credit: NASAThe short pieces of spider silk protein were mixed and fused together under the influence of split inteins, which are naturally occurring and enzymatically active protein sequences. Fibers spun from this microbially produced material replicated the mechanical performance of natural spider silk in terms of tensile strength and toughness. The process also proved more productive than relying on arachnid factories, with output as much as two grams of silk per liter of bacterial culture.

Future research will focus on having the protein-joining reaction occur inside microbial cells so as to skip the step that entails joining the two protein sections. Efforts will also demonstrate the potential to insert other DNA sequences into bacteria to produce other repetitive proteins. The different fibers synthesized may find a range of applications from surgical sutures to underwater adhesives.