Chemical composition of MG
The chemical composition of milled MG was found using the
method from the National Renewable Energy Laboratory (NREL)
(Sluiter and Sluiter, 2010). The chemical composition of MG in this
study (obtained from Tak Province, Thailand) is compared to that
in a previous study (obtained from Nakhonratchasima Province,
Thailand) in Table 1 (Tatijarern et al., 2013). The MG from Tak
Province presents a better candidate for ethanol production due
to its higher percentage of cellulose, which is more preferable as
cellulose is the main source of sugar for fermentation. However,
Tak MG is comprised of a higher percentage of lignin, which could
become degraded during the pretreatment process to produce
inhibitory compounds and hinder ethanol fermentation
(Palmqvist and Hahn-Hägerdal, 2000). The chemical composition
of MG from Tak and Nakhonratchasima province differ considerably
due to a few factors, such as location, climate, and agricultural
practices, for the MG to grow (Malherbe and Cloete, 2002). Tak
province is located in the northern part of Thailand’s mountainous
landscape whereas Nakhonratchasima province is located in northeastern
plateau where drought often occurs. MG from Tak province
thus contains more preferable cellulose which is the main source of
glucose. However, Tak MG is also comprised of a higher percentage
of lignin, which could degrade during the pretreatment process to
produce inhibitory compounds and hinder the ethanol fermentation.
Thus, further research could be done on optimizing the location
of MG and pretreatment method of Tak MG.