The Way Ahead 271bleaching, and dehydrogenases and oxidoreductases for a variety of commer-
cial uses.
In the chemical industry, the possible use of whole-organism hyperthermophiles
offers new ways to produce hydrogen, methane and hydrogen sulphide. At tem-
peratures between 18–80◦C and under anaerobic conditions, this latter gas, for
example can be made byDesulfuromonasfrom elemental sulphur. The conven-
tional chemical catalysis system requires a temperature of 500◦Cormoreto
yield the same result. Unsurprisingly then, the potential of whole-cell microbial
biocatalytic methods and their notably superior specificity, is viewed with great
interest. In future, it may be possible to redesign the configuration of conven-
tional bioreactors to produce efficient, high temperature substitutes for many of
the currently standard industrial processes.
Other extremophiles could also have roles to play. Psychrophiles may yield
enzymes which will function at the low refrigerator temperatures typically
required to avoid spoilage in food processing, for enhanced cold-wash ‘biological’
washing powders and in perfume manufacture, reducing evaporative fragrance
losses. A use has been suggested for halophile enzymes in increasing the
amount of crude oil extracted from wells, though whether this will ever be
a commercial reality remains to be seen and, moreover, leaves aside any
consideration of the ‘environmental’ aspects of increased fossil fuel extraction.
Acidophilic extremozymes may one day form catalysts in chemical syntheses in
acid solution, and alkaliphile derived proteases and lipases may replace existing
versions in washing detergents to enhance their action. In addition, some of
the textile industry’s enzyme-using processes may see alkaliphilic extremozymes
replacements for greater efficiency.
However exciting the prospects of extremophile use may be, turning their
potential into industrially deliverable processes will not be straightforward. For
one thing, many of these organisms are found in very specific and specialised
ecological niches and replicating their optimum environmental requirements is
likely to prove difficult, particularly within bioreactor systems initially designed
around mesophile cultivation. Hence, new types of reactors and, possibly, novel
solid-state fermentation techniques may need to be developed before this can
be achieved. Commercial-scale cultures of extremophiles for extremozyme har-
vesting is also likely to prove problematic, since by virtue of their habitats, it is
rare to find large numbers of any given single species in nature. For such pur-
poses, the isolation and purification of the required microbial culture to be grown
up is generally both difficult and costly to do. Though the extremozymes can
be produced using recombinant DNA methods, as were discussed in Chapter 9,
avoiding the need for wholesale, mass culturing of the extremophiles themselves,
any industrial attempt at whole organism biocatalysis will, of course, demand it.
Despite the clear biotechnological potential of extremophile clean manufac-
turing, a complete comparison between these emergent technologies and con-
ventional methods will inevitably be required before they are likely to gain