Page 277 - Advances in Textile Biotechnology

258 Advances in textile biotechnology

makes it clear (Lyons et al., 2007). Further investigations of structural and
functional properties of resilin are necessary for the development of novel
highly resilient biomaterials.

10.8 Advances and limitations in the biosynthetic
production of recombinant proteins
The increasing power of biotechnology opens new perspectives either to

access rare and limited biological materials in sufficient amounts or to
produce new materials that are based on natural models. Applications of

recombinant protein fibrous materials in commodity materials, textiles,
high-performance composites, and durable and tough materials in general,
require the success of robust and low cost expression systems (Kluge et al.,
2008). The main advantage of protein biosynthesis lies in the ability to
directly and consistently produce high-molecular-weight polypeptides of

exact aminoacid sequence with high fidelity, and, consequently, to have
control over the folded structure functions and assemblies of the resulting
materials. This, in turn, offers an enhanced safety profi le, greater reproduc-
ibility and quality, and the ability of these materials to be tailored to enhance
product performance (Gührs et al., 2000, McMillan et al., 1999, Olsen et al.,
2003). Genetically tailorable composition and sequence to moderate spe-
cific features such as molecular weight, crystalinity and solubility, and the

possibility of subsequent chemical modification confers a signifi cant advan-

tage compared with natural common proteins as they can be modifi ed to
the design of polymeric materials with improved physicochemical proper-
ties such as better defined biocompatibility, bio-recognition, biodegradation

and stimuli sensitivity (Rodríguez-Cabello et al., 2006, Wong Po Foo and
Kaplan, 2002).
Protein-based polymers are environmentally clean over their entire life
cycle from production to disposal; they can be produced from renewable
sources and are biodegradable. The cost associated with the protein polymer
synthesis depends on the cost of the materials used in the synthesis and
scale of the synthesis. Indeed, the synthesis cost of these biosynthetic

methods for producing a well defined and compositionally complex protein
polymer does not increase with the length and complexity of the polymer
after the initial construction of the target gene. This is in contrast to chem-
ically synthesized polymers, in which the cost and complications of large-
scale synthesis often scale with increased architectural control and polymer
molecular weight (Kiick, 2007).
Most of the limitations and disadvantages of the biosynthetic process
have been mentioned previously in connection with the recombinant
expression systems: low accumulation levels of recombinant proteins, lack

© Woodhead Publishing Limited, 2010