Scale-up and optimization of recombinant spider wrapping silk fibre and yarn production.

Spider wrapping silk is one of the toughest known materials, meaning it can absorb more energy per unit mass before breaking than almost any other material. This silk is composed of a single protein, rendering it completely biodegradable. Working together, the Rainey and Liu labs have developed a highly efficient method to produce silk recombinantly using a non-pathogenic strain of bacteria (Escherichia coli). Beyond circumventing the challenges inherent in harvesting silk from spiders, two additional benefits arise: (1) E. coli is extremely tractable to methods of molecular biology that allow direct and straightforward modification of proteins at the level of individual amino acids; and, (2) protein production may readily be scaled up. We have developed ~50 different variations of recombinant spider wrapping silk alongside a novel method to allow automated spinning of fibres. Notably, our automatically spun recombinant silk fibres have mechanical properties rivaling any synthetic material reported to date and are approaching those of native spider wrapping silk. This I2I grant is targeted at scaling-up of our production process for one target wrapping silk-based protein construct, spinning this to yarn, and fine-tuning of its strength and elasticity in the yarn form for textiles applications. Scale-up will be carried out in-house through implementation and optimization of automated fermentation to increase yield and reproducibility over our current manual methods. Novel methods allowing production of yarns from wrapping silk will also be generated. In the longer-term, the Dalhousie team plans to transfer this technology to a Halifax-based spin-off company. Formation of this company will be facilitated by the prototype materials and new processing methodologies made possible by this I2I grant. Intellectual property protection will also be facilitated by this I2I grant, building on an existing provisional patent filed around this technology by Dalhousie University.