Bioprocesses Advance

Aviation fuel and nylon intermediates are among the latest products to benefit from ongoing progress in renewables processing.
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The global aviation industry is committed to reducing greenhouse gas (GHG) emissions by 50% by 2050 compared with 2005. In July, industrial bioscience company Amyris, Emeryville, Calif., partnered with Brazilian airline GOL to fly the industry’s first flight with the renewable jet fuel farnesane. A Boeing 737 made the flight, from Orlando to Sao Paulo, Brazil, using a 10% blend of farnesane. Farnesane is a drop-in fuel; it can be blended directly with petroleum jet fuel without any changes to airplanes, engines or fueling infrastructure.

According to Amyris, farnesane can reduce GHG emissions by up to 80% compared to petroleum fuels. When blended with Jet A/A1 fuel at 10%, farnesane also can cut particulate matter emissions, decreasing pollution near airports and major metropolitan areas, adds the company. Amyris will now begin to quantitatively measure the positive impact to GHG emissions and air quality with every flight using the renewable jet fuel.

In the same month, Genomatica, San Diego, announced that major nylon intermediates — including hexamethylenediamine, caprolactam and adipic acid — are the focus of its third publicly-disclosed development program. The company is developing complete process technologies for the bio-based production of these intermediates, which it will then license to major firms in the nylon value chain. These three chemicals, with a total market of over $18 billion/year, are used primarily in the production of nylon 6 and nylon 6,6, also referred to as the polyamides PA 6 and PA 6,6.

The company says it has validated a number of concepts in its related patent filings, including a successful demonstration of certain metabolic pathways, production of certain nylon intermediates in various microorganisms, and efficient methods to produce and recover certain nylon intermediates from the fermentation.

Meanwhile, with the help of U.S. Department of Energy funding, researchers from the Great Lakes Bioenergy Research Center (GLBRC) at the University of Wisconsin-Madison (UW-Madison), Madison, Wis., have identified the genes and enzymes that create a promising compound — the 19-carbon furan-containing fatty acid (19Fu-FA). Their findings were published in the August 4 issue of Proceedings of the National Academy of Sciences (www.pnas.org/cgi/doi/10.1073/pnas.1405520111).

The compound has a variety of potential uses as a biological alternative for materials currently derived from fossil fuels.
 
“We’ve identified previously uncharacterized genes in a bacterium that are also present in the genomes of many other bacteria,” says Tim Donohue, GLBRC director and UW-Madison bacteriology professor. “So, we are now in the exciting position to mine these other bacterial genomes to produce large quantities of fatty acids for further testing and eventual use in many industries, including the chemical and fuel industries.”

The novel 19Fu-FAs initially were discovered as “unknown” products that accumulated in mutant strains of Rhodobacter sphaeroides, an organism being studied by the GLBRC because of its ability to overproduce hydrophobic compounds. These types of compounds have value to the chemical and fuel industries as biological replacements for plasticizers, solvents, lubricants and fuel additives that are currently derived from fossil fuels. The team also provides additional evidence that these fatty acids are able to scavenge toxic reactive oxygen species, showing that they could be potent antioxidants in both the chemical industry and cells.

Cellular genomes are the genetic blueprints that define a cell’s features or characteristics with DNA. Since the first genome sequences became available, researchers have known that many cells encode proteins with unknown functions according to the instructions specified by the cell’s DNA. But without known or obvious activity, the products derived from these blueprints remained a mystery.

However, researchers have realized that significant pieces of these genetic blueprints are directing the production of enzymes — proteins that allow cells to build or take apart molecules in order to survive. These enzymes create new and useful compounds for society.

“I see this work as a prime example of the power of genomics,” Donohue says. “It is not often that one identifies genes for a new or previously unknown compound in cells. It is an added benefit that each of these compounds has several potential uses as chemicals, fuels or even cellular antioxidants.”