Pollution and Pollution Control - Environmental Biotechnology: Theory and Application - page 86

antimicrobial properties help keep them clean of fouling organisms. Laboratory
modelling of shark skin and the subsequent development of a novel biomimetic
coating technology - known as Sharklet™ - which features biomimetic topog-
raphy replicated in polydimethylsiloxane elastomer has yielded a system which
has proven remarkably effective at inhibiting bio-fouling. The underlying
principle is that both bio-adhesion and surface wet-ability are influenced by
surface micro-topography; by finely replicating the features of pelagic shark-skin
the biomimetic material has shown a zoospore settlement rate less than 85%
that of a conventional smooth surface (Carman et al ., 2006). It has also recently
been shown to inhibit a range of potentially health threatening microorganisms
out of the water, including Pseudomonas aeruginosa , Vancomycin-Resistant
Enterococcus (VRE), Escherichia coli and Methicillin-Resistant Staphylococcus
aureus (MRSA).

Simple bio-substitutions
Not all bio-substitutions need be the result of lengthy chemical or biochemi-
cal synthesis or processing and far simpler forms of biological production may
provide major environmental benefits. The production of biomass fuels for direct
combustion under short rotation coppicing management, described in Chapter 10,
is one example. The use of what have been termed 'eco-building materials'
formed from hemp, hay, straw and flax and then compressed, as an ecological
alternative to conventional materials in the construction industry, is another.
Traditional building approaches have a number of broadly environmental prob-
lems. Adequate soundproofing, particularly in home or work settings where
traffic, industrial or other noises are a major intrusive nuisance can be difficult
or costly to achieve for many standard materials. Walls made from eco-materials
have been found to be particularly effective at sound suppression in a variety
of applications, including airports, largely due to a combination of the intrinsic
natural properties of the raw materials and the compression involved in their
fabrication. In a number of trials, principally in Austria where many of the initial
materials originated, eco-walls were consistently shown to provide significant
improvements in the quality of living and working conditions. Issues of acoustic
insulation often go hand-in-hand with the need for thermal insulation and this
is one area where simple bio-substitution has made a significant impact. Prod-
ucts such as Thermafleece , a high density product manufactured from British

sheep's wool, offer a thermal conductivity of under 0.04W/mK and a density of
25 kg/m 3 making them well suited to the purpose. In addition they also exhibit
exceptional moisture absorption, with a typical 250mm layer of insulation being
capable of absorbing 2 kg of moisture without any significant detrimental effect on
thermal performance. Other natural materials too have become accepted forms of
insulation, particularly with the rise of eco-building and the wider drive towards
low carbon/low embedded energy products in general within the industry, includ-
ing flax, hemp and cellulose. As Table 4.5 shows, they compare very favourably

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