Page 278 - Advances in Textile Biotechnology

Developments in recombinant silk and other elastic protein fi bers 259

of sufficient information on post-translational events (proper folding, gly-

cosylation, phosphorylation, formation of disulfide bridges) and down-
stream processing being the most relevant and commonly found.
Choosing the best expression system mainly requires evaluating the
options in terms of yields, glycosylation, proper folding of the protein of
interest and economics of scale-up, but also of its chemical properties such
as size, isoelectric point, stability at different pHs and temperatures and
proteolitic resistance (Rai and Padh, 2001). Heterologous expression of
proteins has to take into account other aspects such as gene size, because
the size of expressible genes is limited, and the host codon usage.

10.9 Future trends

The textile industry has broadly benefited from the rapid development of
strategic coalitions between the arts of protein engineering and heterolo-
gous protein expression and those of fermentation and bioprocessing tech-
nologies that have led to the possibility of ‘tailoring’ organisms in order to
optimize the production of established or novel materials and of transfer-
ring genetic material from one organism to other.
The advent of recombinant DNA technology and the ability to predict-
ably manipulate the properties of the self-assembly of autonomous units

either scientifically based or derived from functional biological macromol-
ecules and elements of the biosynthetic process, in order to produce refi ned
molecules with a degree of precision that was not possible using conven-
tional synthetic technology, have provided an extremely rich and useful
resource for the design of highly functional recombinant protein-based

fibers with multiple applications. Designing new fibers with particular prop-
erties by using biotechnological approaches or transferring certain advanta-
geous textile properties into micro-organisms, where they can be more
readily reproduced by bulk fermentation, enable smart materials to be
developed with biomimetic or stimuli-responsive properties for ‘intelligent
clothes’.
Because the potential of this genetic engineering technique has not yet
been fully exploited, more complex and sophisticated materials and devices
based on the mechanical properties of elastomeric proteins are expected in
the near future.
Taking into account that genetically engineering protein-based polymers
are produced without the use of any oil-derived raw material and in an
environmentally clean fabrication procedure, the process can be regarded
as a long-term solution to environmental problems usually associated with
many enzymatic transformation processes of textile processing and after
care.

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