With slight modification, the procedure used in Kaparaju and Rintala [8]
was used to measure the methane content of biogas by gas chromatography (GC) (Agilent Technologies 6890N, Ca, USA) using
flame ionization detection (FID) fitted with a Porapak Molsieve 5A
columns. Helium was used as carrier gas with a pressure of 3.0 kg/
cm2 and flow rate of 15 ml/min. Injection and detection temperatures were set at 105 C and 150 C respectively. Detailed characteristics of the substrates are shown in Table 1. The lemon grass
obtained was kept in a dry bucket and was allowed to degrade for
40 days, before it was crushed to smaller particles (about 2 inches
or less) using hammer mill. Similar procedure was used for field
grass [19]. The poultry droppings were sun dried for 15 days, followed by mechanical crushing with mortar and pestle. Lemon grass
was allowed to degrade for 40 days inorder to partially decompose
its lignin, cellulose and other fibrous tissues to enhance a better
performance during the anaerobic digestion.