PRODUCTION OF ARTIFICIAL SPIDER SILK THROUGH YEAST FERMENTATION Emma Ahlgren - Natalie Caracciolo - Anna Goetz

Need for Change in the Textile Industry The Yeast Fermentation Method: A Step Forward Case Study: Bolt Threads

Bolt Threads has pioneered the yeast The global textile industry is a major contributor • DNA samples that mimic natural spider silk proteins are placed in the yeast fermentation method. Gene • Yeast, fed with sugar and water, is allowed to ferment. of environmental waste and pollution. Modification ❖ Biotech company specializing in Process ❖ The textile industry in the US is ranked as the sustainable materials in the fashion 6th largest steam consumer in the country • Ethanol produced from fermentation begins the transcription process of DNA industry. ❖ Agricultural damage caused by use of Transcription • The silk proteins are formed from the amino acids produced during the ❖ Raised $213 million in funding. and translation process. pesticides and soil degradation affects Translation ❖ Aim to produce artificial silk fibers that communities across the world mimic the strength and elasticity of ❖ Chemicals used to clean fibers, which include • Pure synthetic spider silk protein is pushed through a apparatus designed to natural spider silk while minimizing harm mimic a spider’s wart dyes and finishes, account for an estimated Spinning • The resulting silk strands are spun into spools of thread to the environment. Process 20% of industrial freshwater pollution ❖ Committed to sustainability, Bolt Threads The yeast fermentation method of spider silk will complete a life cycle analysis of its production removes these environmental risks The yeast fermentation method process to determine the environmental from the textile manufacturing process begins with inserting modified impacts of the material when compared to spider silk genes in yeast other natural and synthetic materials. batches. ❖ Yeast metabolizes ethanol Feasibility of Bolt Threads Production The Technology of Spider Silk when fermented to stimulate the production of Bolt Threads has hurdles to proteins overcome before it can produce Potential to replace Technical errors in Spider silk possesses a combination of more damaging production process have at a mass scale. production methods led to setbacks strength and elasticity that make it ideal ❖ An ethanol promoter is produced through the Superiority of yeast Quality control concerns Challenges to Production ❖ Streamline fermentation fermentation raise questions about for the textile industry. fermentation process drives the transcription production method reliability of process Potential to scale up Initial high cost requires process to reduce errors. continued funding from ❖ High tenacity and elasticity when process Industry Textile the Changing process to reduce costs investors compared to other textiles ❖ Then the protein is built from the amino acids ❖ Increase the number of ❖ Large stretch ratio formed in the translation process fermentation tanks. ❖ The spider protein formed can be extracted from ❖ Fix quality control concerns. The yeast fermentation method mimics the natural spinning process the yeast ❖ Proteins have a tendency to clump, making spinning ❖ Proteins are secreted into a water bath ❖ The protein is collected from fermentation tanks difficult. ❖ Hydrophobic ends line up to create single long protein chain and purified ❖ Often, process produces a weaker silk than natural spider ❖ Protein is compressed through spinning wart and drawn out of the ❖ The most common method of purification is silk. body chromatography Bolt Threads has also had major successes. Spider silk is superior to common textiles ❖ Purified proteins are compressed through device ❖ It is the first company to bring spider silk garments to market. ❖ Cotton underperforms on measures of strength and elasticity that mimics a spider’s spinning wart ❖ Continues to garner financial support as it expands its ❖ Yeast fermentation can replace the dirtiest part of the traditional ❖ The resulting long strands of silk are passed through production. textile production chain by removing energy consumption and a spinline device to create spools of silk, which can ❖ Has made concrete steps towards addressing the challenges it pollution be woven into fabric faces by focusing on improving its process.