Environmental Engineering Reference
In-Depth Information
2.8 metaBolomIcs In relatIon to BIoenerGy ProductIon
Metabolomics will be important in understanding and improving bioenergy crops, especially in
establishing maximal metabolic efficiency. Metabolomics will also guide metabolic engineering to
ensure carbon is stored in the most accessible form for use in bioenergy production. Metabolomics
may also be important if high-value co-product molecules are being produced in the energy crop.
For example, the production of plastics in plants has been approached by developing the ability
to produce compounds such as polyhydroxybutyrate (Somleva et al. 2008). The production of
high-value co-products may be necessary to ensure that the processing of the biofuel crop is eco-
nomically attractive.
2.9 tarGet traIts For BIoenerGy Plant ImProvement
Identifying traits for improvement in potential bioenergy crops remains a major challenge. A gen-
eral list of these desirable traits is provided in Table 2.1. Many of these are complex traits that are
important targets for dissection using genomic approaches. Additional species-specific traits and
traits suiting specific bioenergy applications need to be added to this list to target specific species
at desired energy outcomes.
The development of second generation bioenergy crops that utilize plant cell walls will be greatly
advanced by an increased understanding of the genomics of cell wall biosynthesis and degradation
(Fincher 2009a, 2009b).
2.10 GenetIc modIFIcatIon to add novel BIoenerGy traIts
Transgenic plants with novel attributes may have superior performance as bioenergy crops. The
expression of enzymes in plants to aid their processing into fuel molecules is a good example of
this. Expression of carbohydrate degrading enzymes (Taylor et al. 2008) that target structural or
nonstructural carbohydrates has the potential to greatly increase the efficiency of biofuel produc-
tion and reduce the cost of conversion of biomass to biofuel. Genes improving lignin degradation
may also be useful in increasing the efficiency of biofuel production (Liang et al. 2008). Genetic
engineering of plants for biofuel production will be aided by genomic knowledge, especially of the
taBle 2.1
traits that may Be considered in Bioenergy crop development
High biomass accumulation
High harvest index
High fraction of biofuel in harvested biomass
Nutrients partition to nonharvested parts
Able to be grown on marginal lands
Harvested material able to be stored in the field
High bulk density
High water use efficiency
High nitrogen use efficiency
Low potential as a weed
High co-product potential
Optimal biomass composition
Large scale of potential production
Low cost of harvest
High suitability for genetic improvement
