Interview Date: August 2008
Dr. Milford Hanna
From the Special Topic of
In our analysis of biofuels research over the past decade,
the work of Dr. Milford Hanna ranks at #1 by total citations.
His 1999 Bioresource Technology paper, "Biodiesel
production: a review," (Ma FR and Hanna MA, 70: 1-15,
October 1999), is the most-cited paper over the past decade in
our analysis, with 300 citations.
Reuters, Dr. Hanna's work ranks in the top 1% among
researchers worldwide in the field of Agricultural Sciences. He has also
been named a Highly Cited Researcher in this field.
Dr. Hanna is the Director of the Industrial Agricultural Products
Center and the Kenneth E. Morrison Professor of Biological Systems
Engineering and Food Science & Technology at the University of
In the interview below,
ScienceWatch.com talks with Dr. Hanna about his highly
cited work, including his research on biofuels.
Please tell us a little about your research
and educational background.
I received my B.S., M.S., and Ph.D. in agricultural engineering from The
Pennsylvania State University in 1969, 1971, and 1973 respectively. I
taught agricultural engineering at California State Polytechnic State
University for two years before joining the agricultural engineering
faculty at the University of Nebraska in 1975. Since about 1980, my
research program has had a heavy emphasis on bioprocess engineering and
more specifically on finding new industrial (non-food) uses for
agricultural commodities such as corn and soybeans.
"In my mind, it is important that we
think in terms of alternate fuels (biofuels)
being used to reduce the increase in
petroleum-based fuels use, as opposed to reducing
the use of the same."
What prompted you to publish on biofuels?
In 1979, I had the opportunity to get involved in biofuels research because
of then-"high" gas prices, a regional interest in soybean utilization, and
interest from a graduate student to work in the biodiesel area.
Your most-cited paper in our biofuels Special Topic
is the 1999 Bioresource Technology review, "Biodiesel
production: a review." Would you sum up the major points of this paper
for our readers?
This manuscript reviews the ways vegetable oils and animal fats can be
processed for use as mobile fuels with a particular emphasis on the
state-of-the-art of the transesterification process, which is the generally
accepted method of converting fats and oils to biodiesel today.
In 2005, you published another review, "Biodiesel:
current perspectives and future," (Journal of Scientific &
Industrial Research 64: 854-7, November 2005). What had
changed in the field between the 1999 paper and this one?
The industry, although still in its infancy in 2005, had developed
significantly since 1999. There were numerous biodiesel production
facilities in operation. Reality was beginning to set in that there would
be a shortage of available fats and oils for biodiesel production,
certainly in terms of being able to replace a significant amount of the 40
to 50 billion gallons of diesel fuel that are burned in the USA annually.
From a production standpoint, researchers and processor were getting
serious about improving the transesterification process through the use of
heterogeneous (as opposed to homogeneous) catalysts and being able to use
lower-quality feedstocks such as used cooking oils and animal fats.
Blending biodiesel with ethanol and diesel fuel (EB-diesel), the advantages
of EB-diesel, and the potential performance problems were being discussed
It's now been almost three years since that last
review—have there been any more significant developments in
biofuels since then? What future can you predict for biofuels
I don't know that there is a particularly different emphasis in the area of
biodiesel research today but (1) the interest in heterogeneous catalysts
remains strong and needs further development; (2) the need for alternative
oilseed production is apparent; and (3) glycerol (by-product) utilization
needs to be brought into focus.
"Reality was beginning to set in that
there would be a shortage of available fats and
oils for biodiesel production, certainly in terms
of being able to replace a significant amount of
the 40 to 50 billion gallons of diesel fuel
that are burned in the USA
Judging by your publication record, you also do a
lot of work with extruded starch acetates. What is the significance of
Starches are used to a significant extent to produce water-soluble
(environmentally and biodegradable) packaging "peanuts." The water
solubility aspect limits the use of starch to such a use and even limits
its use within that application because it presents some performance
issues. Starch acetate is much less water soluble and can, in fact, be made
virtually water resistant. Such a characteristic lends itself to much
broader and higher-value applications such as egg cartons, meat trays, and
disposable plates. The shortcoming, at this point, is the cost of
What should the "take-away lesson" about biofuels
be for the general public?
In my mind, it is important that we think in terms of alternate fuels
(biofuels) being used to reduce the increase in petroleum-based fuels use,
as opposed to reducing the use of the same. As countries such as China and
India develop, their use of petroleum-based fuels continues to increase
significantly, in direct competition with the US for the available oil.
Overall, conservation and improved efficiency need to become part of our
strategic energy-use plan. These offer opportunities for significant
reductions in energy use, which should, at least, reduce the rate of
increase in use.
Milford A. Hanna, Ph.D.
University of Nebraska
Lincoln, NE, USA
Hanna's most-cited paper with 300
cites to date:
Ma FR and Hanna MA, "Biodiesel production: a review,"
Bioresource Technol. 70(1): 1-15, October 1999.
Source: Essential Science Indicators from Thomson