Traditional and Emerging Feedstocks for Food and Industrial Bioproduct Manufacturing - Food and Industrial Bioproducts and Bioprocessing - page 25

range of soil types at thirty-one different sites spread over seven states in crop producing
regions of the United States during the late 1980s and early 1990s (Wright et al ., 2005 ).
Several species, including sorghums, reed canarygrass, wheatgrasses and switchgrass were
identified as having merit for further development. It was also recommended that perennial
grasses be given high research priority.
Switchgrass ( Panicum virgatum ), a C4 perennial grass, produces a significant amount of
biomass (5-11 tonnes/ha); it has relatively low lignin (about 6%) and high cellulose and
hemicellulose contents, 32% and 36%, respectively (Schmer et al ., 2008 ; Karp and Shield,
2008). The US Department of Energy has selected switchgrass as one of the dedicated high
energy crops for biofuel production. Advantages of switchgrass over other potential biofuel
feedstocks include relatively high and reliable productivity across a wide geographical
range, suitability for growth on marginal quality land, perennial growth habit and low water
and nutrient requirements (Sanderson et al ., 1996). Yet, it may take up to two years to
establish switchgrass for production.
Miscanthus ( Miscanthus sacchariflorus and Miscanthus sinensis ), which used to be an
ornamental plant in the United States, is receiving increased attention as a dedicated energy
crop in the United States and Europe (Karp and Shield, 2008; Villamil et al ., 2008 ). Similar
to switchgrass, miscanthus is an herbaceous perennial crop that is capable of producing a
significant amount of lignocellulosic biomass. Yet, miscunthus may take two to three years
to establish, delaying its full production. It has been reported that miscanthus could produce
significantly higher biomass than switchgrass (about 18 vs. 14 tonnes/ha) (Boehmel et al .,
2008). Furthermore, miscanthus has a higher cellulose content (about 58%) than switchgrass
(about 32%) (Sanderson et al ., 2007 ). Reed canarygrass ( Phalaris arundinacea L.),
napiergrass ( Pennisetum purpureum Schumach.), bermudagrass ( Cynodon spp.), aleman
grass ( Echinochloa polystachya ), elephant grass ( Pennisetum purpureum ), fox tail millet
( Setaria italica ), straw and stalks of grain crops and sweet sorghum, and sugarcane bagasse
are also being examined for their viability to produce lignocellulosic biomass for bioethanol
production. Extensive reviews on chemical composition and yield potential of these crops
have been published (Sanderson et al ., 2007 ; Simmons et al ., 2008 ; Karp and Shield, 2008 ;
Byrt et al ., 2011 ; Wright et al ., 2005 ).
1.5 CONCLUSIONS
According to the 2006 Vision Goals established by the Biomass Research & Development
Technical Advisory Committee, 25.1 million tonnes of products would be produced from
biomass by 2030 (BTAC, 2006). Expansion of the bio-based product manufacturing industry
will exert tremendous pressure on feedstock resources and environment. Advancements in
biomass production systems and efficient and environmentally benign manufacturing
technologies are essential for the global success of sustainable bio-based economies.
Increasing feedstock needs will require significant improvements in traditional crop production
yields, development of alternative and dedicated crops and efficient use of biomass resources.
Biotechnology will play a crucial role in the development of new or modified traditional crops
with desirable physical, chemical and agronomic properties, increased production yields and
even in the expression of health beneficial and high value compounds at elevated levels in
crops for biofarming. Demand for food and feed sources will continue to grow with already
increasing global population. Hence, development of non-food alternative crops that can grow
on marginal quality soil with minimal inputs (water and nutrient) is a high priority.