Preliminary study on oil extraction and biogas production from Cymbopogon nardus (Serai Wangi)

Abstract

Abstract An essential oil from Cymbopogon nardus has many benefits, specifically in pharmaceutical, cosmetics and perfumery fields. However, extraction of Cymbopogon nardus produces abundant waste which usually left to decay naturally. The present study evaluated biogas potential from Cymbopogon nardus waste through anaerobic digestion method with rumen fluid as inoculum. The presence of methane which is the main gas that makes up the composition of biogas is verified by using GC-FID and Biogas Analyser. The waste was collected from the oil extraction of various part of Cymbopogon nardus plant. The experimental study on the extraction is important to identify the oil yield from various part of Cymbopogon nardus plant. The extraction was done through steam distillation with temperature varied from 40 °C to 100 °C. The comparison of oil yield from various part of the plant was done with an aid of GC-MS analysis. It was found that the leaf of Cymbopogon nardus contains most essential oil, which gives the highest oil yield about 1.5 % at 100 °C followed by the stem (0.3 %). The oil yield found in the plant flower was less than 0.3 % and none found in the root. Extraction at 100 °C resulted in higher oil yield compared to 40 °C, 60 °C and 80 °C. The citronellal content was the highest compound presents in the oil followed by geraniol. The average generation of biogas on the other hand were range from 0.4 ml/day to 12.5 ml/day. The F/I ratio which produced the highest volume of biogas is 10 (w/w).