This Small Business Innovation Research (SBIR) Phase II project proposes to develop a platform for the production of spider silk fibroins in plant trichomes. Synthetic spider silk has great potential as an environmentally-friendly biomaterial because it is very flexible yet has a tensile strength greater than steel. A great need exists for a scalable strategy for spider silk fibroin production in a renewable heterologous system that will allow efficient harvest and recovery. The platform is a natural mechanism for protein production and purification in the plant Nicotiana tabacum. The technological innovation is the targeted expression of spider silk fibroins within the gland cells of leaf surface structures called glandular secreting trichomes. The research objectives will be to optimize the production of spider silk fibroins and generate fibers from harvested proteins. The goal is to drive the expression of different spider silk fibroins in trichomes using patented promoters, and refine methods of fibroin recovery, so that fibers with differing physical properties can be generated and tested. This work will demonstrate further that spider silk fibroins can be produced by plant trichomes in a cost-effective manner, and will allow the large-scale, photosynthetic production of next-generation biomaterials.
What are the broader impacts of the proposed activity?
The broader impact/commercial potential of this project, if successful, will be to demonstrate that a variety of synthetic spider silk fibroins can be produced in a plant-based system, and to better understanding the biosynthetic hardware of the specialized plant structures called glandular secreting trichomes. This work will allow the development of novel ways of achieving industrial biomaterial production without the use of toxic chemicals, and will thus have great societal impact by decreasing the necessity of utilizing large amounts of hazardous compounds in industrial processes. The commercial impact of this project will implement a platform for the photosynthetic production of environmentally-friendly biomaterials.
Proteins can be used in scientific research, as medicines and to generate commodities like biofuels. Despite their widespread utility, proteins are often difficult and expensive to produce even when generated in biological hosts such as bacteria or yeast. Typically, extensive downstream purification steps add significant costs to protein production strategies. Plants are ideal production systems because they only require soil, light, and water to generate protein, but in the past, recovering protein from plants was overly complex and inefficient. In this Small Business Innovation Research (SBIR) Phase II project, PhylloTech developed and optimized technology that allows the production of proteins in plants without the need for expensive purification steps. PhylloTech utilized leaf surface structures called glandular secreting trichomes to produce and recover both spider silk, a biomaterial that historically has been difficult to express in other systems, and industrial enzymes used to make biofuels. Additionally, PhylloTech successfully scaled up plant growth and optimized protein recovery with innovative harvesting techniques. The trichome-mediated protein expression system generated during this project is now a commercial platform that can be utilized for the large-scale production of high-value proteins in plants. Protein targets, including biomaterials and industrial enzymes, can be produced and harvested in an environmentally-friendly, photosynthetic system.
