Sustainable Fuels & Chemicals (The Century of Biology: Part II.IV)

The nearly $10 trillion chemicals and fuels industries dig up hydrocarbons and then turn them into nearly every physical good we use in our day to day lives from plastic to laundry detergent to running shoes to fertilizers. Efforts to de-carbonize these industries have attracted tens of billions of dollars in investment, much of it going to bio-based approaches. In fact, many of the pioneering companies in the biomanufacturing industry like LanzaTech, Amyris, and Genomatica founded two decades ago to make these commodities using fermentation instead of oil. They’ve made tremendous progress over the years in terms of science & engineering, product development, scale, and price:

  • Science & engineering: Two good displays of progress in the companies’ technical efficiencies can be seen in the graphs below showing Geno’s BDO titer productivity and LanzaTech’s CO utilization curves over time.
  • Product development: Amyris and Geno cut development times of their molecules from 2-4 years in the early 2010s to 6-10 months today. Geno's BDO took 27 months to reach a commercializable titer (50 g/L), whereas their second molecule only took 10 months, and is probably faster today as this was back in 2014.
  • Scale: Amongst other products, Amyris is producing 1,500 tons of squalene and selling DTC in their cosmetics brands, Geno is making 30,000 tons of BDO and Lanzatech is cranking out 60,000 tons of ethanol. All have plans to ramp capacity fast and extend their platforms as discussed above. Geno and LanzaTech are both building new plants to increase scale to 100,000 tons in Geno's case and tenfold to 600,000 tons in LanzaTech’s in the next few years. Another company specializing in the fermentation of sustainable aviation fuel (SAF) has 50,000 tons of capacity live and another 435,000 tons of manufacturing capacity being built.
  • Price: All these improvements have helped these companies traverse down the cost curve. LanzaTech’s ethanol is cost competitive with incumbents’, Geno’s BDO is closing in on parity as it approaches 4% of the $17B market, Amyris lowered the price of its their first commercial product farnesene 4x in four years

Several particularly interesting models to biomanufacture chemicals have emerged, namely that of using waste products as feedstocks and cell-free enzymatic catalysis. Three major companies in the space use employ different variants of the first approach. LanzaTech uses steel and iron mill emissions as its carbon source for the 60K tons of ethanol it produces a year. Its ethanol and jet fuels boast 65 and 80% less GHGs emissions relative to fossil fuels, respectively. Meanwhile, Enerkem converts residual biomass and non-recyclable municipal solid waste into biofuels and renewable chemicals, resulting in 60% reduction in GHGs.[1] Additionally, a Nature paper described a new method for using solar power to convert CO2 and H2O into butanol and hexanol with overall conversion efficiency of 8%. 

Second, Solugen uses a cell-free catalytic process with CRISPR engineered enzymes that is far more efficient that traditional fermentation methods and can be retrofitted to use CO2 as a feedstock instead of its current use of corn sugars, as described in this article:

It’s possible to use fermentation to make the same chemicals from plants instead of fossil fuels, but fermentation is also inefficient—if you use living cells to turn sugar into a chemical, half of the sugar will be converted into CO2. Solugen’s approach is designed to eliminate that waste. At the plant, which runs on wind power, corn syrup goes in a reactor filled with engineered enzymes, making an intermediate product that goes in another tank with metal catalysts, which speed up the whole reaction and make it more efficient. Virtually all of the feedstock is ultimately converted into the final product.
Based on a detailed analysis of current products, the company estimates that it could theoretically produce 90% of the chemicals that are now produced by fossil fuels. (The other 10% include chemicals that the company doesn’t want to produce because of the environmental impacts of the chemical itself.) Making alternatives for everything will take time—the company has to design enzymes for each chemical, and that’s a challenging process that isn’t necessarily guaranteed to work.
The products are also less expensive to make than traditionally-produced chemicals in part because the company’s process is far safer. Using corn syrup instead of petroleum helps; the enzymes also work without the use of other fossil fuels that are normally used in processing, and the chemistry happens at room temperature rather than in ultra-hot equipment that risks catching fire. Traditional processes “are so intrinsically unsafe, that you cannot build those plants in the United States anymore,” says Chakrabarti. “You have to go to foreign countries who have much lower safety standards.” Building a plant costs around three times as much as it did in the 1970s, even adjusting for inflation, because of current safety standards, says Hunt.
In juxtaposition, the site where Solugen now works used to be a petrochemical plant until it violently exploded, shattering windows at nearby businesses and sparking a fire that took seven hours to put out.
The process can also happen in plants that are much smaller than the traditional version, and less capital-intensive to build. The company plans to build a distributed network of plants that can help reduce the emissions from transportation. It’s possible to reuse old industrial facilities, like the first plant in Houston. “If you look at the old steel towns, old manufacturing towns of pulp and paper mills, they all have the same infrastructure in place where we can go and revitalize effectively these communities that have been economically depressed for many years because of the loss of manufacturing jobs,” he says.

Here are some of the top companies using biological methods in fuels & chemicals:

Read next section: circular plastics

[1] Another exciting company to flag in this category is Origin Materials, though it uses a chemistry-based approach.