www.checkbiotech.org ; www.raupp.info ; www.czu.cz

The idea that bioenergy will become the white knight of the 21st century is
intuitively attractive, and receives much press, across a broad range of
political and social agendas. However, on a detailed development level it
remains unclear how bioenergy will allow a sustainable platform for
continued world economic growth, November 2005
by James McLaren.

Einstein said that "problems cannot be solved by the same level of
thinking that created them" -- solutions to the energy crisis will require
different ways of thinking.

Shifting from a petro-driven economic base to a bio-based foundation is a
significant challenge and success will require more than just "substitution"
strategies. There is a need to clearly understand the magnitude of the
problem, to accept that new breakthroughs in technology applications are
required for any chance of success, and to acknowledge that acceptance of
dramatic change is probably required before we can begin to build a more
sustainable future.

The problem is straightforward and can be quantified with reasonable
accuracy. The world currently utilizes 420 quads/year (quad = 1015 Btu) and
the conservative case projection is that within 30 years the world
requirement will be 650 quads/year, largely due to economic development in
India and China.

While energy demand is growing rapidly, fossil fuel reserves are finite. In
addition, if the current global temperature elevation is even partly related
to anthropogenic gas emissions then what will happen during the projected
massive increase in the use of fossil fuels? A conceptually attractive
feature of bioenergy is that carbon dioxide release will be at least neutral
due to carbon recycling on a relatively short time-scale.

Currently, bioenergy and bio-based inputs account for less than 5% of all
basic inputs to the existing Western economy. While several
government-industry initiatives1 have highlighted the issues and challenges,
and some companies have also taken steps to embrace the emerging
bio-industry, the pace of change may be too slow. Moving from 5% of inputs
to >50% of inputs in less than 20 years is a "moon-shot" type of challenge.

Current Situation

First, it is important to define what "biomass" really means?while there are
several meanings being associated with this word, for the purposes of this
article biomass is taken as any output from primary production (i.e., plant
materials).

Traditional biomass can make a useful contribution to bioenergy production
and, in recent years, biofuels have been on the leading edge of
developments. For example, in 2004, approximately 3.4 billion gallons of
ethanol fuel were produced in the US for blending as an oxygenate in
gasoline. In this commercial case, the biomass used was largely maize starch
(~95%), sorghum starch (~4%), and a small amount of other crop inputs.

The application of new production technologies, conventional plant breeding,
and early-stage biotechnology traits, have resulted in significant yield
increases (at the same level of inputs) in maize. Hence, an increasing
volume of grain has been made available for conversion into ethanol with no
negative impact on the feed/food segments of the market.2

Lignocellulose biomass has been considered as a potential feedstock for
biofuels and other bioenergy3 (e.g., gasification and the generation of
electricity as well as steam). Lignocellulose is an abundant material
created from solar energy in primary production. Theoretical calculations of
conversion to ethanol indicate high potential to generate 25 to 50 billion
gallons of ethanol per year.

However, lignocellulose is a complex material (lignin, cellulose, pectin)
and is not easily converted into biofuel in an economically viable manner.
Consequently, progress over more than 20 years of research into conversion
technologies has been disappointing in terms of creating an overall viable
process for lignocellulose to ethanol.

The current use of biomass (for biofuels) is heavily focused on the
development of complex conversion technologies, typically involving a
fermentation step. It is only very recently that the first indications of
change in the feedstock have appeared. For example, the major maize seed
companies have screened their germplasm for hybrids that produce a higher
fermentation yield in the dry-mill process.4 The results indicate that
genetic components for higher ethanol do exist, but these have never been
specifically targeted in the past.

Major crop plants have been bred (genetically altered via recombination and
recurrent selection) primarily for food or feed production, and when was
there ever selection pressure to optimize for industrial biofuel traits in
wild plants? It would seem there is a huge opportunity to optimize plants
for use in bioenergy strategies.

Applications of biotechnology

Biotechnology is a tool that provides an opportunity to design and optimize
the feedstock materials, not just the microbial bioconversions in the
process. For example, for corn-based ethanol, the particular traits now
being explored for improved ethanol production include overall starch
production (yield per unit impacts efficiency), starch types
(amylose:amylopectin ratios), and compositional interactions. For
lignocelluose, much progress has been made on enzymatic conversion of
cellulose to ethanol, but the lignin and other components inhibit the
overall process.3 Several research groups are now exploring the outcome when
lignin biosynthesis is down-regulated --potentially a major breakthrough in
moving lignocellulose into the commercial biofuel market.

The preceding comments are focused on ethanol only because it is currently
the major biofuel. A very analogous situation exists for biodiesel (methyl
esters of plant fatty acids, although recycled cooking oil and animal fats
can be used) where the market potential is high but limited by the current
overall economics. Strategies that focus on stacking industrial traits, for
example, in specifically-designed non-feed soybeans, could open the door to
directed design for improvements in subsequent bioenergy use.

There is much written about the future potential of a "hydrogen economy."
Nevertheless, it is widely recognized that some inherent technical hurdles
may take 10 ? 15 years to resolve. Assuming success with those, there
remains a need to have an energy source (hydrogen is an energy carrier, not
a source) to drive the hydrogen economy. In schools of thought, the current
assumption is that fossil fuels (reformulated natural gas) will be the main
source, which seems to be a self-defeating achievement. Nuclear power
appears to be a more logical choice. However, why would biomass not be a
high priority, at least to be explored as a major energy source for a future
hydrogen-based system.

Research is ongoing into the use of ethanol to power bio-fuels cells.5
Biotechnology could also be a valuable tool to explore the possibilities of
improved solar energy capture via plants with biosynthesis of material that
facilitate energy transfer to hydrogen.

Currently, a number of bio-based products are made from various parts of
different crops. The classic example is pulp/paper from lignocellulosic
biomass. Others include specialty fibers, adhesives, boards, veggie-candles,
crayons, and additives. However, to-date, and with the exception of paper,
most have been small niche products due to difficulties in processing and/or
product performance issues.

Biotechnology really opens several new doors to creating "natural" bio-based
products that are viable in contributing to a more sustainable future. For
example, 1,3-propandiol (to be used for a polymer that replaces
petro-derived polyester) can now be generated from a microbial bioconversion
of starch-derived glucose, a process that required 18 genetic-driven changes
in the biosynthetic pathway.6

A large number of exciting opportunities exist to utilize natural polymers,
rather than petro-polymers, for future needs with functional as well as
resource advantages. The current well-known example is the spider silk
protein that is very light but is stronger than steel. Since it is difficult
to harvest spider webs, biotechnology is being used to express the protein
in situations where high levels can be produced and harvested with relative
ease.

[www.isb.vt.edu]

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