Reviewer Comments - EERE

2011 Algae Platform Review – Reviewer Comments
Reviewer Comments are direct transcripts of commentary and material provided by the Platform’s
Review Panel. They have not been edited or altered by the Biomass Program.
6. Overall Impressions
Please provide an overall evaluation of the project, including strengths, weaknesses, the project approach,
scope, and any other overall comments.
Reviewer Comments
Reviewer: 1
There shold be more comfort in the project and its outcomes than I register. There seem to be many
details that one needs to know before one could nod in agreement. I fear that more experiments would be
the more likely result. The production of light organic acids may not be a valuable outcome. However,
this may just set the stage for a separate project beyond this.
Reviewer: 3
A main objective of this effort is to achieve low cost enzymatic hydrolysis and complete carbohydrate
fermentation of biomass feedstock. - What are the cellular biochemical targets of the purported
fermentation? - What are the products to be developed by this approach? These specifics are a must for
the proper evaluation of the project.
Reviewer: 5
Very nice presentation of a local resource utilization project.
Reviewer: 6
Overall a good project that is well done. Solid pathways considered. Looking at three pathways? What are
the criteria for comparison? Seaweed digestion. Ends up a dirty liquid (pigments et al). How does one
purify the fuel and how does one dispose of the fermentation media? What is the go no go criteria? How
do alcohol yields compare against simple AD of chicken manure adn methane gas produciton (and on site
combustion?)
Reviewer: 7
My strongest impression is that the potential fuel volumes are too low and too dispersed geographically to
be a viable transporation fuel source. The capital and production cost estimates indicate that this
technology has very big hurdles for economic viability.
Presenter Response
I think that the “comfort” issue may be that much of the project has been working to down select from
three to one preferred process pathway. The initial investigations were done at a preliminary level. We are
currently focusing on the ketonization pathway and I believe that the data we are generating will help to
develop a higher level of comfort. Now that we have selected the ketonization route as the preferred
pathway, our final product is primarily isopropyl alcohol along other secondary alcohols. Optimally we
would like to see higher proportions of longer chain alcohols, as these are more compatible with gasoline
infrastructure. This in turn requires fermentation s that accumulate larger quantities of butyrate and other
longer chain acids.
Criteria of comparison between the three pathways were yield, energy balance, cost and ease of
implementation. The ketonization pathway won out on energy balance and ease of implementation. Ease
of implementation was critical in order to make progress on the time line we had set for ourselves. The
seaweed digestion does turn dark. So far, we have found that purifying the fermentation broths is not
necessary when using the ketonization route. The other organic materials from the fermentation media
that accompany the carboxylate salts into the ketonization reaction appear to contribute to the chemistry
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