human growth hormone (Leite et al. 2000), industrial polypeptide (Guda et al.
2000), lactoferrin (Nandi et al. 2002), wound-healing agent: human factor XIII
(Gao et al. 2004), vaccine anticanine parvovirus (Molina et al. 2004), antithreat
agent (anthrax), antigen-type vaccine (Koya et al. 2005), human insulin (Nykiforuk
et al. 2006), bovine aprotinin (Tissot et al. 2008), human tpa (Hahn et al. 2009),
collagen (Stein et al. 2009), and tissue repair agent elastin (Floss et al. 2010). The
former examples are, mostly whole-plant approaches for the production of proteins
used as pharmaceuticals and other plant-made industrial products. They show
clearly that the use of plant systems as bioreactors for heterologous proteins has a
great potential for industrial, therapeutic, and nutritional applications.
Other plant-based systems used as bioreactors have been developed, e.g., tissue
cell cultures and suspended cell cultures which have been transformed with stable
or transient expression constructs for protein production; the latter avoids the
integration of the transgene to the genome of the plant system used as protein
factory. In vitro transient expression of foreign proteins in plant cell and tissue
cultures represents an advantage to avoid restrictions to use stable transgenic
plants in the open field.
The bottleneck for both stable and transient assays, using viral vectors or
T-DNA constructs, is that the accumulation of the transgene in callus and suspended cell cultures is generally low. Nevertheless, the recent work by Shadwick
and Doran (2007) showed that hairy roots provide a better system to increase plant
virus replication, pointing to hairy root cultures as a potential system for in vitro
production system of foreign proteins encoded in plant viral vectors.
Using these systems it has been possible to produce diverse bioactive metabolites, of which we list some of the most recent: The anticancer metabolite taxane
(Syklowska-Baranek et al. 2009), antioxidant betalains (Georgiev et al. 2010),
ginsenosides (Mathur et al. 2010), the analgesic harpagoside (Grabkowska et al.
2010), and the antimicrobial phytoalexin (Kawauchi et al. 2010) are some examples.
More recently, hairy roots have been proposed as a system for vaccine production and delivery (Skarjinskaia et al. 2013) and for the synthesis of novel and
potent sweeteners of protein molecular nature (Pham et al. 2012).
The explosive increase in the use of microalgae deserves special mention.
These organisms have become one of the favorite bioreactor systems for the
synthesis of diverse products; recently there has been a boom in the production of
biofuels using microalgae bioreactors (Chisti 2007; Wijffels and Barbosa 2010).
However, algae-based systems have been used in the production of several
exogenous molecules, including products that have importance in the cosmetic or
food industry, and they have also been used for the massive production of
endogenous bioactive molecules such as vitamins, pigments, and lipids; a detailed
description of several approaches can be consulted from several excellent reviews
(Walker et al. 2005; Raja et al. 2008; Potvin and Zhang 2010).
More recently, microalgae-based bioreactors started to be used as an alternative
for the production of foreign-recombinant proteins on a large scale (Mayfield and
Franklin 2005). Using such approaches it has been possible to produce a fulllength IgG antibody using Chlamydomonas reinhardtii chloroplast, (Tran et al.
15 Plants as Bioreactors for Human Health Nutrients
445
2000), lactoferrin (Nandi et al. 2002), wound-healing agent: human factor XIII
(Gao et al. 2004), vaccine anticanine parvovirus (Molina et al. 2004), antithreat
agent (anthrax), antigen-type vaccine (Koya et al. 2005), human insulin (Nykiforuk
et al. 2006), bovine aprotinin (Tissot et al. 2008), human tpa (Hahn et al. 2009),
collagen (Stein et al. 2009), and tissue repair agent elastin (Floss et al. 2010). The
former examples are, mostly whole-plant approaches for the production of proteins
used as pharmaceuticals and other plant-made industrial products. They show
clearly that the use of plant systems as bioreactors for heterologous proteins has a
great potential for industrial, therapeutic, and nutritional applications.
Other plant-based systems used as bioreactors have been developed, e.g., tissue
cell cultures and suspended cell cultures which have been transformed with stable
or transient expression constructs for protein production; the latter avoids the
integration of the transgene to the genome of the plant system used as protein
factory. In vitro transient expression of foreign proteins in plant cell and tissue
cultures represents an advantage to avoid restrictions to use stable transgenic
plants in the open field.
The bottleneck for both stable and transient assays, using viral vectors or
T-DNA constructs, is that the accumulation of the transgene in callus and suspended cell cultures is generally low. Nevertheless, the recent work by Shadwick
and Doran (2007) showed that hairy roots provide a better system to increase plant
virus replication, pointing to hairy root cultures as a potential system for in vitro
production system of foreign proteins encoded in plant viral vectors.
Using these systems it has been possible to produce diverse bioactive metabolites, of which we list some of the most recent: The anticancer metabolite taxane
(Syklowska-Baranek et al. 2009), antioxidant betalains (Georgiev et al. 2010),
ginsenosides (Mathur et al. 2010), the analgesic harpagoside (Grabkowska et al.
2010), and the antimicrobial phytoalexin (Kawauchi et al. 2010) are some examples.
More recently, hairy roots have been proposed as a system for vaccine production and delivery (Skarjinskaia et al. 2013) and for the synthesis of novel and
potent sweeteners of protein molecular nature (Pham et al. 2012).
The explosive increase in the use of microalgae deserves special mention.
These organisms have become one of the favorite bioreactor systems for the
synthesis of diverse products; recently there has been a boom in the production of
biofuels using microalgae bioreactors (Chisti 2007; Wijffels and Barbosa 2010).
However, algae-based systems have been used in the production of several
exogenous molecules, including products that have importance in the cosmetic or
food industry, and they have also been used for the massive production of
endogenous bioactive molecules such as vitamins, pigments, and lipids; a detailed
description of several approaches can be consulted from several excellent reviews
(Walker et al. 2005; Raja et al. 2008; Potvin and Zhang 2010).
More recently, microalgae-based bioreactors started to be used as an alternative
for the production of foreign-recombinant proteins on a large scale (Mayfield and
Franklin 2005). Using such approaches it has been possible to produce a fulllength IgG antibody using Chlamydomonas reinhardtii chloroplast, (Tran et al.
15 Plants as Bioreactors for Human Health Nutrients
445