Page 261 - Advances in Textile Biotechnology

242 Advances in textile biotechnology

proper folding and therefore the activity of some proteins and hence lower

efficiency in introducing the foreign DNA into the host cells (Mahmoud,
2007).

10.4.3 Plants

Recombinant production of proteins in plants has many advantages com-
pared with other expression systems. These include the potential for rapid
agricultural scale production at an extremely competitive cost, the avail-

ability of established practices for their efficient harvesting, transporting,
sorting and processing, the absence of human pathogens, the ability to fold
and assemble complex proteins accurately and the possibility of governing
sub-cellular targeting (seeds or endoplasmic reticulum) instead of the secre-
tory pathway, thus affecting the interlinked processes of folding, assembly

post-translational modification and long-term storage. Plants can also be
used in large-scale microbial-like fermentation production facilities by using
plant-cell suspensions. The range of recombinant proteins made in plants
has extended to include industrial enzymes, technical proteins that are used
in research, milk proteins that are a suitable nutritional supplement, and
new protein polymers with both medical and industrial uses. There is little
doubt that recombinant antibody production in plants is likely to have a
great impact on human health. Protein polymers that have been produced
in transgenic plants include human collagen, a synthetic spider silk and
bovine elastin, the latter being produced at low yields (Ma et al., 2003).
Several challenges remain to be met in plants in terms of increasing

yields, lack of sufficient information on post-translational events, down-
stream processing and addressing biosafety (the main perceived risks are
transgene spread by pollen dispersal and horizontal gene transfer, and the
effects of potentially toxic recombinant proteins on herbivores, pollinating
insects and micro-organisms in the rhizosphere. There is also concern that
plant material that contains recombinant proteins could inadvertently enter
the food chain) and acceptability issues, as well as industry inertia (Ma
et al., 2003).

10.4.4 Insects

The use of recombinant baculoviruses such as the nuclear polyhedrosis
virus of the ‘fall armyworm’ Autographa californica (AcNPV), of the silk-
worm Bombyx mori (BmNPV) or of the gypsy moth Lamantria dispar
(LdNPV) and insect tissue-culture cells have demonstrated considerable
−1
advantages. These include: high protein yields up to 30–500 mg L ,
large scale production, and the option of expressing proteins with post-
translational modifications and others that would otherwise be toxic at high

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