Chemistry Reference
In-Depth Information
Fig. 14.6
Levulinic acid as a platform chemical.
Fig. 14.7
Chemical building blocks
available from carbohydrates.
commercially viable applications have appeared
[101]. Recently, Iowa State University and RTI began
an investigation of levoglucosan hydrolysis to give
simple sugars that can be fermented to organic acids
or ethanol [102].
Lignin also has been investigated as a chemical
feedstock, e.g. in the production of quinones [103],
and has been suggested widely as a component in
graft copolymers or polymer blends [104]. The use
of lignin in the chemical industry is limited mostly
to very low value applications, such as drilling muds,
asphalt additives and fillers in concrete [87]. The
highly heterogeneous structure of lignin and the
resulting difficulty in converting it to a single product
have hindered its use as a chemical feedstock.
starting to be realised. Most examples of the use of
organisms or enzymatic steps in the production of
chemicals has been limited to low-volume, high-
value fine chemicals and pharmaceuticals such as
oligosaccharides, amino acids, purines, vitamins,
nicotine or indigo [40,105]. This is a sensible first
application, given the strict structural requirements
of many of these speciality materials. Biocatalysts are
generally unchallenged in their ability to provide the
stereo-, regio- and enantioselectivity required by
these speciality products. However, bioprocesses also
possess some attractive features that suggest they
would be useful for the greening of larger scale
operations [106]. The utility of biotechnology in the
production of bulk chemicals has been reviewed and
an economic evaluation of the necessary technology
has been presented [91]. The development of more
robust biological systems that can operate in extreme
conditions (temperature, low water levels, in organic
solvents, high hydrostatic pressure) also will broaden
their applicability [107].
The industry is not without examples of reason-
5.3 Bioproduction of chemicals in industry
The most successful route so far for introducing
renewables to the chemical industry has been
through biotechnology, although its use for the
green production of large-volume chemicals is only
