Fundamentals of Biological Intervention 51as to offer significant advantages over existing traditional processes. Many current
industrial procedures generate pollution in one form or another and the chal-
lenge of such ‘green chemistry’ is to design production systems which avoid the
potential for environmental contamination. The implementation of ‘clean man-
ufacturing technologies’ demands considerable understanding, innovation and
effort if biologically derived process engineering of this kind is to be made
a reality. With environmental concerns placing ever growing emphasis on energy
efficiency and low carbon usage, industrial applications of the life sciences in
this way seem likely to be increasingly relevant. To date, however, there has
been little commercial interest in the extremophiles, despite their very obvious
potential for exploitation.
The existence of microbes capable of surviving in extreme environments has
been known since the 1960s, but the hunt for them has taken on added impetus in
recent years as possible industrial applications for their unique biological capa-
bilities have been recognised. As might be expected, much of the interest centres
on the extremophile enzymes, the so-called ‘extremozymes’, which enable these
species to function in their demanding natural habitats. The global market for
enzymes amounts to around $3 billion (US) annually for biomedical and other
industrial uses and yet the ‘standard’ enzymes typically employed cease working
when exposed to heat or other extreme conditions. This often forces manufactur-
ing processes that rely on them to introduce special steps to protect the proteins
during either the active stage or storage. The promise of extremozymes lies in
their ability to remain functional when other enzymes cannot. The potential for
the mass use of enzymatic ‘clean production’ is discussed more fully in the fol-
lowing chapter, but the major benefit of using extremophile enzymes in this role
is that they offer a way to obviate the requirement for such additional procedures,
which inevitably both increases process efficiency and reduces costs. In addition,
their novel and distinct abilities in challenging environments allows them to be
considered for use as the basis of entirely new enzyme-based approaches to pro-
cessing. Such methods, if properly designed and implemented, have the potential
to give rise to major environmental and economic benefits compared with tra-
ditional energy-intensive chemical procedures. However, the widespread uptake
and integration of biocatalytic systems as industrial production processes in their
own right is not without obstacles which need to be overcome. In many conven-
tional catalytic processes, chemical engineers are free to manipulate turbulence,
pH, temperature and pressure for process intensification, often using a variety of
reactor configurations and regimes to bring about the desired enhancement of pro-
ductivity (Wright and Raper 1996). By contrast, in biological systems, the use of
turbulence and other such conventional intensification methods is not appropriate
as the microbial cells are typically too sensitive to be subjected to this treatment,
as are the isolated enzymes. Such procedures often irreversibly denature proteins,
destroying enzymatic activity.