2. Napier Grass (Pennisetum purpureum Schumach)
as Raw Materials
Napier grass belongs to herbaceous tropical species, native
to the east Africa and has high dry matter productivity with
moderate forage quality in southern Kyushu [27]. The
species is widely used for animal feeds [28], phytoremediation
activity of heavy metal [29] and biofuel feedstocks [30].
The species is originally perennial in the tropical and
subtropical areas, while it is necessary for the species to
adapt to the winter season in the temperate areas such as
southern Kyushu for maintaining the perennial property
[31]. Organic digested animal manure or sun-dried leguminous
leaves as green manure can replace chemical fertilizers
for both animal and biofuel feedstocks production to reduce
energy consumption and allow comparable productivity in
Napier grass [32]. Napier grass has wide variation of
phenotypes, reflected by plant breeding due to the crossing
of dwarf genotype and relative species such as pearl millet
(Pennisetum americanum) [33,34]. Dwarf variety of lateheading
type of Napier grass (dwarf Napier grass) originated
from Florida, USA, via Thailand [35] was assessed to be
suitable for both grazing [36] and cut-and-carry systems
among several sites of southern Kyushu, Japan [37].
We have continued to use this dwarf type of Napier
grass for the biological ethanol production [22,25,26] and
photocatalytic hydrogen production [38]. Another type of
Napier grass such as Pennisetum purpureum L Schumach
and Merkeron were also used for bio-fuelization to
methane [39] and bio-ethanol production [19], respectively.