Monday, March 23, 2015

Bold predictions for biofuel production by Joule Unlimited published in BiofuelsDigest on 23 March 2015

BiofuelsDigest ran a story on 23 March 2015 titled Joule says “will go commercial in 2017″: solar fuels on the way.

With the story is the text

The company has previously indicated that it could produce up to 15,000 gallons of diesel fuels, per acre per year, and as much as 25,000 gallons per acre per year of ethanol — so think in terms of 15 million to 25 million gallons for this first commercial facility, as an ultimate nameplate capacity.

The significance of this resides in the meaning ascribed to the word "could." Of relevance to this point is the text in the BiofuelsDigest post:

It comes down to the production efficiency of the organism — a set of cyanobacteria that directly produce alcohols and alkanes, rather than producing an entire plant of which only a fraction is converted to ethanol. Plus, the photosynthetic efficiency of the Joule process. As we reported in 2011 from a peer-reviewed article in Photosynthesis Research:

“The solar-to-product conversion efficiency of Joule’s direct, continuous process for producing diesel, ethanol and chemicals is between 5 and 50 times greater than any biomass-dependent process, and gains additional efficiencies by avoiding downstream refining…Joule’s combined advances in genome engineering, solar capture and bioprocessing result in photosynthetic conversion efficiency of more than 7% relative to available yearly solar energy striking the ground.”

The referenced paper by Joule Unlimited A new dawn for industrial photosynthesis assumes a photosynthetic efficiency [7.2%] and then calculates the energy equivalent of C17 produced at that energy efficiency. There is no experimental data showing actual formation of C17 in an amount 15,000 gallons C17 per (acre-year).

See the IPBiz post
Steven Chu to Scientific American on biofuels on 7 March 2012

One notes that the ratio of the heats of combustion nC17/ethanol which is 47.2 to 29.7 or 1.6 is comparable to the ratio of the areal yields 25/15 or 1.7. If one has fixed yield by assuming a certain energy conversion, one requires more gallons of ethanol than gallons of nC17, because of ethanol's lower enthalpy of combustion. Thus, one might infer the 25,000 gallon per acre year number arises from assuming one can convert the energy of the 7.2% efficiency entirely into the energy of combustion of ethanol, and the 15,000 number corresponding to the conversion to the energy of combustion of n-C17.

IPBiz links:

Followup on 3/24/15:

Note Joule's US patent 8,986,964 with first claim


1. A method for production of ethanol, comprising: culturing an engineered cyanobacterium in a culture medium in the presence of light and inorganic carbon, wherein said engineered cyanobacterium comprising a recombinant pyruvate decarboxylase nucleic acid sequence encoding a pyruvate decarboxylase having EC and a plurality of recombinant alcohol dehydrogenase nucleic acid sequences encoding an alcohol dehydrogenase having EC or EC, wherein the expression level the alcohol dehydrogenase and the expression level of the pyruvate decarboxylase are regulated by separate promoters, wherein the expression level of alcohol dehydrogenase in the engineered cyanobacterium is greater than the expression level of alcohol dehydrogenase in a control engineered cyanobacterium comprising a recombinant alcohol dehydrogenase nucleic acid sequence and a recombinant pyruvate decarboxylase nucleic acid sequence regulated together by a single promoter, and wherein the engineered cyanobacterium produces ethanol in an amount greater than a non-engineered cyanobacterium, when cultured under identical conditions.

See also Example 3.


Post a Comment

<< Home