This 12-part series highlights women-led ventures in the green economy.An estimated 1.2 billion pairs of jeans are sold each year worldwide. The magic behind this timeless piece of clothing is none other than the 50 shades of blue — indigo to be precise.Indigo is a color, a plant and a specific molecule. And while there are 5,000-year-old traditions of using natural indigo in places such as India, Japan, and Guatemala, most indigo on the market today is derived from non-renewable fossil fuels — and thus unsustainable.But Tennessee-based Stony Creek Colors (SCC) is changing that. Started in 2012 by Sarah Bellos, SCC is the first company in the United States to grow the indigo plant at a scale usable by the commercial denim industry.Bellos studied natural resource management in college and ran susty agriculture groups on campus. A classic ESTP ("the entrepreneur") personality type, Bellos had a knack for entrepreneurship and founded her first business with her sister in Nashville. "Our first business was in a pretty cottage industry, selling naturally dyed clothing at festivals, art events and Whole Foods," Bellos elaborated. Through this first business, Bellos found there was a market from brands that wanted to use natural dyes: "There were no commercial dye houses at the time working with natural dyes, so we stepped in to fill this void."Bellos determined that the source of natural dyes would have to be managed for consistency and volume if they were to reach industrial scale. A feasibility study funded by a USDA Value Added Producer Grant helped the farmer-entrepreneur settle on indigo. Unlike other natural colors such as black walnut (used for brown colors), natural indigo can be a drop-in replacement for the synthetic kind.The difference between synthetic and natural indigo is how the indigo is made, not necessarily how the indigo is used. The key distinction: carbon comes from a decomposed dinosaur (synthetic) or carbon is pulled from the atmosphere in the last month by a nitrogen-fixing, carbon-sequestering plant (natural). "For a truly sustainable solution, the source material must be renewable,” Bellos noted. By shifting the textile dye source from petrochemical to plant-based, "we can actually sequester carbon in both soil and product." SCC only harvests the leaves of the indigo plant so that they can put stem back into the Earth. Based on SCC’s typical harvest scenario per season and two-leaf regrowth cycle, the estimated carbon captured per acre from their indigo is about 3,500 pounds.  Based on SCC’s typical harvest scenario per season and two-leaf regrowth cycle, the estimated carbon captured per acre from their indigo is about 3,500 pounds. Regenerative agriculture, or agriculture that restores the carbon content of the soil, Is the 11th most impactful solution to climate change according to Project Drawdown. At scale, regenerative agriculture practices, including no tillage, no pesticides and synthetic fertilizers, and diverse cover crops, can mitigate about 23 gigatons of carbon dioxide by 2050.Synthetic indigo makes up more than 99 percent of the indigo dye market. Most is made from a single, vast factory in Inner Mongolia. In the mainstream process, indigo synthesis requires feedstocks such as benzene and formaldehyde and high temperatures from coal fired power plants; the process creates reaction byproducts such as ammonia gas and sodium sulfite.With such a highly consolidated commodity market, it’s difficult for natural indigo to compete on pricing: for about 10 grams of dye needed to dye a pair of blue jeans, it costs 5 cents for synthetic indigo and $1.25 for natural indigo. The environmental and social costs of producing synthetic dye are not adequately (or at all) factored into the market price. According to Bellos, "it takes a half a pound of cyanide to make one pound of synthetic indigo, plus several other toxic or carcinogenic chemicals." In contrast, SCC’s feedstocks are grown in backyards, with no supplemental crop irrigation required in Tennessee.Bellos received critical support in the early development of commercializing the U.S. production of the indigo plant. The United States Department of Agriculture provided two phases of SBIR grants, and the National Science Foundation recently has granted SCC an STTR award. Seed and Series A round investors include Jumpfund (an investor network investing in female-led startups in the Southeastern U.S.), Serious Change, Propel Capital and Village Capital.The innovation for SCC continues. Blue is one of the scarcest colors found in nature. As food and personal care companies transition to natural colorants and safer chemicals, the void in versatile blue options is palpable. As food and personal care companies transition to natural colorants and safer chemicals, the void in versatile blue options is palpable. Not only is SCC pioneering in sustainable land use, textiles and dyes, but it also illustrates the value of coupling a low-carbon product with economic development. SCC is the first project to be awarded a USDA SBIR in Tennessee and employs 14 "hardworking, innovative and resourceful" people, said Bellos. The staff has a wide range of backgrounds. The technical team includes masters and Ph.D level scientists, including chemists, a plant scientist and engineers. Early on as it scaled from pilot to production, SCC struck gold by bringing on an accomplished mechanical engineer who previously managed a 3M production plant.The chemistry lab, greenhouse, and factory are based in Springfield, Tennessee, and the agriculture team can be found interfacing with farmers, harvesting indigo, or at the SCC research farm location. Similar to Emrgy employing former oil and gas professionals, SCC recruits former tobacco growers to produce their crop. This is further evidence that many incumbent industries are slowly being replaced by innovations in the green economy.Working in regenerative agriculture requires a resilient and diverse team. "The environmental parameters are shifting all of the time and there is no ‘average year’ in agriculture," explained Bellos. In addition, SCC is developing a complete value chain for the industrial production of indigo, which includes complex logistics for seed and feedstock production, harvest, transportation, and chemical extraction and processing.Bellos is an innovative thinker who is equally interested in the rural development and science sides of the business. Her key qualities are patience, vision and grit. The next challenge for Bellos will be to take the company post Series A into a high growth phase, expanding beyond denim and building new markets. SCC will need to find the opportunities that permit it to maintain profitable unit economics while finding the right production, engineering and operations staff. Creating this roadmap and delivering results requires SCC to be nimble and forward-looking. Bellos is up to the task.