Renewable Jet Fuel 

General Biomass Company develops advanced enzymes which convert nonfood biomass to glucose and other biosugars for renewable jet fuel and bioplastics.

Cheap sugars from biomass are the key to the sustainable production of low-carbon renewable jet fuel.

Why Aviation Biofuels?

Aviation biofuels are essential because continuing to burn fossil fuels is not sustainable. Second-generation biofuels are sustainable, with low impact on land or water used for food crops. Aviation biofuels are cleaner, with around an 80% reduction in CO2 lifecycle emissions compared with fossil jet fuel.

Aviation biofuels are practical. Second-generation biofuels can now be mixed with existing aviation fuel supplies at up to 50%. As of 2011, Bio-SPK (BioDerived Synthetic Paraffinic Kerosene) jet fuels meet the new ASTM standard D7566, developed through extensive engine and flight testing, and are certified for use at 50/50 blends for commercial jet aviation. Similar fuels have been tested and certified for military operation in a variety of aircraft.

Further information on aviation biofuels is available from the Air Transport Action Group and RenewableJetFuels.org, a project of Richard Branson's Carbon War Room.

Pathways to Renewable Jet Fuel

Renewable Jet Fuel comes from feedstocks produced by green plants, which absorb atmospheric CO2 and convert it to sugars and oils which can be made into low-carbon jet fuel. The leading process for renewable jet fuel today is HRJ (Hydroprocessed Renewable Jet), also known as HEFA (Hydroprocessed Esters and Fatty Acids). The base feedstocks are seed oils from oil-seed plants like Jatropha and Camelina. These oils are subjected to a catalytic process which converts the raw purified oil to biojetfuel which meets or exceeds current fossil jet fuel standards.

ATJ (Alcohol to Jet Fuel) converts shorter carbon chain alcohols like butanol to the longer C12-C15 alkanes of jet kerosene. ASTM approval of ATJ is pending. ATJ would use sugar rather than oil seed feedstocks, and thus potentially provide larger amounts of jet fuel.

Sugar to Jet Fuel

The manufacture of either biojetfuel or biodiesel from plant seed oils or waste fats and grease is relatively straightforward. This has allowed relatively small amounts of drop-in renewable jet fuel to be developed quickly.

The problems now are cost and scale. Seed oils make up only a small fraction of plant biomass. Some, such as Palm Oil are also used for food. A potential solution to these problems is the use of engineered organisms such as heterotrophic algae (e.g. Solazyme), yeasts, and bacteria to produce plant oils or other renewable hydrocarbons in large quantities by fermentation of biosugars from lignocellulosic biomass.

This approach takes advantage of the much greater amount of cellulosic biomass sugars as compared to seed oils. The problem then shifts to how to produce large quantities of cheap sugars from biomass. Plant oils have the longer carbon chains needed to produce alkanes in the C12-C15 size range characteristic of jet fuel kerosene. Plant sugars are C5 or C6, and about 2/3 of the sugar is consumed by growth and metabolism of the production organisms. This lower efficiency is acceptable if there is enough biomass feedstock (there is - over a billion tons per year in the U.S., two billion tons worldwide), and if the cost of the biomass sugar is low enough.

Direct chemical conversion of sugars to deoxygenated alkanes or intermediates like gamma-valerolactone (e.g Virent) can reduce the amount of sugar needed and thus potentially lower the cost of jet fuel production from sugars. The theoretical maximum (weight alkane/weight sugar) conversion (e.g., glucose to hexane) is about 47%, due to the loss of oxygen atoms which are heavier than carbon atoms. This has a direct impact on the delivered price of biobased jet fuel. Highly pure specific sugars are needed for both chemical catalytic and fermentation methods.

New and better enzymes developed by General Biomass attack this problem directly by enabling the use of a wide variety of biomass feedstocks, such as municipal solid waste (MSW), construction and demolition waste (CDW), and millions of cubic meters of beetle-killed wood (BKW) in the U.S. and Canada. All of these forms of dead biomass are cheaper, available today, and are less controversial than food-based sources of sugar like corn.

General Biomass Enzymes

Enzymatic methods have the advantage that they preserve the original C6 glucose molecules made by photosynthesis, and with appropriate technology will have lower capital costs and ease of use. Additionally, enzymatic methods preserve and make available the two other biomass components, xylan and lignin. Xylans can be hydrolyzed by our enzymes to yield the C5 sugar xylose, raising the total sugar output from biomass by 50%. Lignin can either be burned as a substitute for coal, or converted to high value chemicals for adhesives, fuel additives, and carbon fibers for light-weight composites in aircraft and vehicles.

Enzymatic methods require the application of sophisticated biotechnology for their development, but once developed are relatively easy to produce and use with minimal energy and capital inputs. Their principal product, glucose, is at the core of all cellular metabolism, and is thus a feedstock for most industrial fermentations producing biofuels, bioplastics, and renewable chemicals. In effect, glucose is the new oil, but based on local sources, creating local jobs, and contributing far less to global warming. Local biomass feedstock sources, processed by General Biomass enzymes, enable fuel production for both commercial and military needs at a variety of locations around the world.

We provide pure biomass deconstruction enzymes, specific cellulases and hemicellulases, selected and customized for your application, lowering risk in the R&D and pilot phases, lowering costs at commercialization.

Contact us today and let us help you develop the best enzyme solution for your needs.

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