Contents
5.1 Introduction..................................................................................................................... 130
5.2 Sugarcane Is More Than Sucrose .................................................................................. 132
5.3 Sugarcane Biofactory for High-Value Biopolymers ..................................................... 133
5.4 Sugarcane Biofactory for Protein Products ................................................................... 135
5.5 Sugarcane Biofactory for High-Value Carbohydrates and Alternative Sugars............ 136
5.6 Potentialities and Challenges of Sugarcane as a Biofactory ........................................ 139
5.7 Conclusions and Future Perspectives ............................................................................ 143
References................................................................................................................................ 143
5.1 Introduction
Modern sugarcane, the main source of sucrose worldwide, belongs to the grass
family (Poaceae) and was created about a century ago from the combination of
Saccharum polyploid species. According to Daniels and Roach (1987), the genus
Saccharum comprises six different species: S. barberi, S. edule, S. officinarum,
S. robustum, S. sinense, and S. spontaneum. Of these, S. officinarum (the domesticated sugar-producing species) and S. spontaneum (a vigorous wild species with
many aneuploidy forms) are thought to be the ancestors of cultivated sugarcane.
S. officinarum originally derived from S. robustum, while S. barberi and S. sinense
are thought to have been derived by crossing S. officinarum and S. spontaneum
(Asano et al. 2004; Sandhu et al. 2012). However, Irvine (1999) suggested only
two true species: S. officinarum and S. spontaneum, and therefore, current sugarcane commercial cultivars are thought to be hybrids with 80–90 % of the genome
from S. officinarum and 10–20 % of the genome from S. spontaneum (Grivet et al.
1996; Hoarau et al. 2002).
The chromosome number of these species ranges from 36 to 200 (Asano et al.
2004; OGTR 2011). The polyploid and aneuploid nature of the genus Saccharum
has made phylogenetic analyses and, as a result, breeding programs a tough task.
Furthermore, the taxonomy and phylogeny of sugarcane is complicated as plants
from five genera are thought to share common characteristics and form a closely
related interbreeding group known as the ‘‘Saccharum complex’’. This complex
comprises the genera Saccharum, Erianthus section Ripidium, Miscanthus section
Diandra, Narenga and Sclerostachya (D’Hont et al. 1998; OGTR 2011), albeit
controversial discussions still remain in the scientific community concerning the
genetic relationships among genera in this complex and new hypotheses are being
formulated. As a consequence, the assumption that S. officinarum is a result of a
complex introgression between S. spontaneum, Erianthus arundinaceus, and
Miscanthus sinensis (reviewed by Daniels and Roach 1987) is being analyzed in
the light of new biochemical and molecular approaches. Accordingly, current
extant species of the genera Saccharum, Erianthus, and Miscanthus are clearly
distinct in their isozyme profiles, nuclear and cytoplasmic restriction fragment
130
F. C. Gómez-Merino et al.
5.1 Introduction..................................................................................................................... 130
5.2 Sugarcane Is More Than Sucrose .................................................................................. 132
5.3 Sugarcane Biofactory for High-Value Biopolymers ..................................................... 133
5.4 Sugarcane Biofactory for Protein Products ................................................................... 135
5.5 Sugarcane Biofactory for High-Value Carbohydrates and Alternative Sugars............ 136
5.6 Potentialities and Challenges of Sugarcane as a Biofactory ........................................ 139
5.7 Conclusions and Future Perspectives ............................................................................ 143
References................................................................................................................................ 143
5.1 Introduction
Modern sugarcane, the main source of sucrose worldwide, belongs to the grass
family (Poaceae) and was created about a century ago from the combination of
Saccharum polyploid species. According to Daniels and Roach (1987), the genus
Saccharum comprises six different species: S. barberi, S. edule, S. officinarum,
S. robustum, S. sinense, and S. spontaneum. Of these, S. officinarum (the domesticated sugar-producing species) and S. spontaneum (a vigorous wild species with
many aneuploidy forms) are thought to be the ancestors of cultivated sugarcane.
S. officinarum originally derived from S. robustum, while S. barberi and S. sinense
are thought to have been derived by crossing S. officinarum and S. spontaneum
(Asano et al. 2004; Sandhu et al. 2012). However, Irvine (1999) suggested only
two true species: S. officinarum and S. spontaneum, and therefore, current sugarcane commercial cultivars are thought to be hybrids with 80–90 % of the genome
from S. officinarum and 10–20 % of the genome from S. spontaneum (Grivet et al.
1996; Hoarau et al. 2002).
The chromosome number of these species ranges from 36 to 200 (Asano et al.
2004; OGTR 2011). The polyploid and aneuploid nature of the genus Saccharum
has made phylogenetic analyses and, as a result, breeding programs a tough task.
Furthermore, the taxonomy and phylogeny of sugarcane is complicated as plants
from five genera are thought to share common characteristics and form a closely
related interbreeding group known as the ‘‘Saccharum complex’’. This complex
comprises the genera Saccharum, Erianthus section Ripidium, Miscanthus section
Diandra, Narenga and Sclerostachya (D’Hont et al. 1998; OGTR 2011), albeit
controversial discussions still remain in the scientific community concerning the
genetic relationships among genera in this complex and new hypotheses are being
formulated. As a consequence, the assumption that S. officinarum is a result of a
complex introgression between S. spontaneum, Erianthus arundinaceus, and
Miscanthus sinensis (reviewed by Daniels and Roach 1987) is being analyzed in
the light of new biochemical and molecular approaches. Accordingly, current
extant species of the genera Saccharum, Erianthus, and Miscanthus are clearly
distinct in their isozyme profiles, nuclear and cytoplasmic restriction fragment
130
F. C. Gómez-Merino et al.