Endorsements
Quite a few American and foreign ethanol producers
and potential clients have tested the Purdue yeast, and all of them were
quite impressed with the yeasts’ performance. The following are excerpts
written by industrial colleagues commenting on these yeasts and our
efforts.
Dr. Charles A. Abbas
Director of Yeast and Renewable Research, Archer Daniels Midland Corp.
Oct 25, 2002
Dear Dr. Ho:
Thank you for allowing us to conduct fermentation research using your
recombinant yeast. ….. We have successfully tested your organism on the
mixed-sugar media generated from corn fiber. Your (the Purdue) organism
has been the most promising of all the non-recombinant and recombinant
organisms that we tested under the specific parameters of our tests. The
fermentation media was high in inhibitory compounds, including acetic
acid, hydroxymethyl furfural, and furfural...
Mr. Larry W. Denny
President, Biomass Processing Technology, Inc
...Your accomplishment ranks as the most significant single accomplishment
for the exploitation of biomass...
Dr. Robert E. Lumpkin
Vice President, Swan Biomass Company
...The development of the recombinant glucose/xylose co-fermenting yeasts
was a technical breakthrough by Dr. Ho. For years, other microbiologists
attempted to exploit a different, more direct route to engineering yeast
to ferment xylose and glucose simultaneously. They all failed. Dr. Ho
found a more elegant, indirect approach, and has been able to make it work
despite some theoretical objections by her peers. She has had to overcome
a great deal of skepticism about her approach in the academic community to
secure the funding for research.
The unique technology used to create LNH can also be used to create
engineered yeasts that ferment sugars to products other than ethanol. At
the present time, Dr. Ho is focusing on ethanol production, and has been
unable to divert resources to other products. However, there is no reason
that organisms producing a variety of industrious-important chemicals
cannot be pursued in the future using the techniques discovered and
patented by Dr. Ho.
I have been selecting and sponsoring university-based research programs
for major oil companies for over 25 years, and have worked with many
others in industry, both in my own company and in others, who utilized
university research. Dr. Ho's work is among the very best from a
scientific standpoint, and far and away the best from an economic
standpoint. The occasional spectacular success like Dr. Ho's is what
insures continued private sector support for academic research.
Mr. Robert Benson
Vice President, R&D/Technical Service, Tembec Chemical Products Group,
Canada
...As you know our industrial alcohol plant ferments spent sulfite liquor
(wood hydrolysates) with Saccharomyces cerevisiae. This allows us to
produce 15M liters per year of high quality ethyl alcohol. We could
increase our production by 30% if we could ferment the xylose sugar
present in our liquor. We have been looking for more than 15 years for a
xylose fermenting yeast, which can survive in spent sulfite liquor.
We have evaluated many native and genetic recombinant strains, which were
ineffective. To date other laboratories using genetic engineering
techniques have been unsuccessful in their attempts to ferment xylose in
our plant waste streams. In contrast your yeast has provided exciting
results. Although our studies are not complete we continue to believe that
your genetic engineering work provides the only real chance of achieving
pentose fermentation on an industrial scale...
Dr. Ting Carlson
Sr. Research Scientist, Cargill North American Corn Milling
...Dr. Ho is one of the most persistent scientists I know who over the
past 15 years worked on a very challenging research topic on engineering
yeasts to ferment pentose sugars. She has demonstrated that old fashion
hard work does pay off even in science and constructed the only
pilot-scale tested glucose/xylose fermenting recombinant yeast on wood
hydrolysates.
Generally, laboratory constructed recombinant microbes tend to fail in an
industrial production condition, either from the lack of genetic stability
or from the lack of tolerance to real- life fermentation substrates. In
the case of biomass conversion to ethanol, xylose containing wood
hydrolysates is extremely toxic to microbes due to the presence of wood
extractive impurities. Dr. Ho anticipated and addressed these issues by
engineering a very robust yeast strain and made it readily usable for
industries.
Dr. Ho's accomplishment in this area is significant as it relates to our
country's need to be energy self- sufficient. Due to her persistence, we
now have an option in economically converting woody biomass to ethanol...