The single demonstration flight is expected to occur after Gevo receives ASTM International certification for its fuel, sometime in mid- to late-2015. Gevo has been working through the rigorous ASTM process for six years, which includes extensive engine testing and data analysis by all of the major original equipment manufacturers to establish the specification for this drop in fuel. Once approved, this fuel can be seamlessly integrated into the distribution infrastructure and onto commercial aircraft.

Gevo developed proprietary technology that uses a combination of synthetic biology, metabolic engineering, chemistry and chemical engineering to focus primarily on the fermentative production of isobutanol, as well as related products from renewable feedstocks.

Gevo has also developed and demonstrated the technology to convert isobutanol into aliphatic and aromatic hydrocarbons using known chemistry and existing refinery infrastructure:

• Isobutanol produced from starch or biomass is dehydrated over an acidic catalyst to produce isobutylene, which is then further reacted to product mixtures of longer chain aliphatic hydrocarbons.

• A portion of this material is reacted separately to form high density aromatic compounds.

• Hydrogen gas, a byproduct of the aromatization reaction, is used to remove unsaturated bonds in the aliphatic material.

• The hydrocarbons then are blended in proportions that can meet all ASTM standards for fuels: isooctane is a dimer of dehydrated isobutanol and is a major component of the premium value alkylates, a key gasoline component; a trimer of the isobutylene (dehydrated isobutanol) is a jet fuel blend stock; a polymer of four and five isobutylenes can make a diesel blend stock.

A number of organizations have explored or are exploring the use of Gevo’s ATJ, including the US Navy (earlier post); NASA (earlier post); Lufthansa (earlier post); the US Air Force (earlier post); and the US Army (earlier post).

Alaska Airlines was the first US airline to fly multiple commercial passenger flights using a biofuel from used cooking oil. The carrier flew 75 flights between Seattle and Washington, D.C. and Seattle and Portland in November 2011. The airline has set a goal to using sustainable aviation biofuel at one or more of its airports by 2020.