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.
Reviewer Comments
Reviewer: 1 Criteria Score: 2
I have difficulty following the relevance. Can we not use US samples from northern waters? Will algae
culture in northern waters make any economic sense? How does flue gas factor in the relevance?
Reviewer: 2 Criteria Score: 4
The relevance of the strain discovery is unclear; more nutrient demand and lipid production
characterization will be needed, based upon information presented. What is the sustainability (buffering
of flue gas supply of CO2 etc.)?
Reviewer: 3 Criteria Score: 5
The work addresses goals in the area of Feedstock Supply Ft-B. Sustainable Production: By utilizing
information generated by resource assessment (SNL) culture conditions can be established to match
optimal deployment area. Ft-C. Feedstock Genetics and Development: Genetic diversity in algal culture
collection will provide strains with potential for commercialization of algal biofuel production in vast
area of North America beyond the southeastern US and gulf states.
Reviewer: 5 Criteria Score: 3
Although project goals are relevant to biomass program goals, there was no plausible explanation why
this project would be successful in producing algal strains that would thrive in full scale production
systems.
Reviewer: 7 Criteria Score: 3
The work is very unlikely to lead to advancement in biofuel technology.
Presenter Response
3.A. We believe that Canadian water samples have the potential to provide strains better suited for local
deployment. Although, this may only provide a slight improvement in our overall probability of success,
the water sampling was a task for the NRC. Hence there was no advantage to choosing US water samples.
At the moment, even optimistic estimates for algal biofuel production costs without benefit of a high
value co-product indicate that this approach cannot compete with petroleum. As I noted in my
presentation, productivity in northern latitudes will make it even harder to compete on a straight biofuel
production basis. The challenge for all will be to identify value-added co-products that are scalable with
biofuels. Meeting that challenge is even greater for areas that are less than ideal for maximum
productivity. There is a great deal of information in the literature regarding the toxicity of high
concentrations of CO2 as well as the contaminating gases found in flue gas. Most of this work deals with
enrichment cultures or small bench scale cultures grown from dilute inocula. Careful analysis of the body
of work suggests that the problem was not the toxicity of the gas components, but rather, the acidic nature
of CO2, NOx and SOx, but that is an unproven hypothesis. Therefore, to be certain that the strains
isolated would be able to thrive with flue gas as a CO2 source, we planned our enrichments to isolate only
strains that were robust enough to survive the challenge of simulated flue gas. As I noted, the enrichment
cultures in well buffered media provided robust growth. This prompted us to modify our media
formulation and the results support the hypothesis that the problem with flue gas is more a pH issue than a
toxicity issue. 3.B. I agree that strain characterization is essential, and that has begun at NRC with the
transfer of our current culture collection. The buffering was necessary for small scale enrichments and
culture growth because pH control was not practical for the number of cultures being grown. But
extensive buffering is not necessary for larger scale cultures. The pH shifts caused by CO2 dissolution
can be used to control CO2 feeding using pH probes to control gas addition valves. This process is used
to great success by our NRC colleagues. 3.C. See response 1.C. 3.D. The DOE algal biofuels roadmap
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