DOI: https://doi.org/10.55373/mjchem.v25i1.101

Keywords: Xylose; hydrolysis; autoclave assisted; lemongrass leaves

Abstract

Lemongrass (Cymbopogon species) is an aromatic plant that is cultivated mainly as a source of essential oils. It is a perennial species grown extensively in tropical and subtropical regions around the world. Lemongrass leaves (LL) are a waste product generated by the agricultural industry that is rich in lignocellulosic material such as lignin, cellulose and hemicellulose. Xylose is a sucrase inhibitor which is very useful as a functional sugar complement to inhibit blood glucose levels from rising. Autoclave-assisted acid and alkaline hydrolysis methods were used to extract xylose from lemongrass leaves. The yields obtained were used to determine the most efficient hydrolysis method for xylose extraction. The acid and alkaline hydrolysis of lemongrass leaves were performed using a range of hydrolysis times (10 - 150 min), initial acid/alkali concentrations (0.6 % - 5 %), solid-liquid ratios (1:30 - 8:30) and temperatures (105 - 140 °C). The maximum xylose yield via acid hydrolysis was 69.57 g/L, under the optimum conditions of 90 min hydrolysis time, 0.8 % sulphuric acid, a solid-liquid ratio of 1:5 and an autoclave temperature of 125 °C. However, with alkaline hydrolysis the maximum yield achieved was only 4.119 g/L, under optimum conditions which were 120 min hydrolysis time, 2% sodium hydroxide, a solid-liquid ratio of 2:15 and autoclave temperature of 125 °C. Thus, acid hydrolysis was much more efficient in the production of xylose compared to alkaline hydrolysis.