Effective cellulose isolation from torch ginger stem by alkaline hydrogen peroxide – Peracetic acid system

Abstract

Efficient and eco-friendly isolation of cellulose from non-woody plants is paramount. This study aimed to isolate cellulose from torch ginger stem (Etlingera elatior) (TGS) waste efficiently by alkaline hydrogen peroxide pre-treatment and subsequently by peracetic acid treatment (AHP-PAA) under autoclave conditions (121 °C/0.1 MPa). A complete randomized design with three factors—AHP concentration (0, 16, and 33 % (v/v) H2O2 in 5 % (w/v) NaOH), PAA concentration (PAA to water ratio of 0.36, 1.14, and 4.00 (v/v)), and pre-treatment time (30, 60, and 90 min)—was used to investigate changes in yield and fiber’s chemical components. The results showed that TGS is a potential non-wood cellulose source with a high S/G ratio (3.016) and low SiO2 (4.2 %). Analysis of variance exhibited that the AHP and PAA concentration affected lignin-related parameters, but pre-treatment time influenced only carbohydrate-related parameters. The optimum isolation condition resulted in 47.78 % pulp yield with 64.78 % α-cellulose, 34.06 % hemicellulose, 0.15 % lignin, and 71.8 % crystallinity in 90 min of reaction time. Massive liberation of individual fibers from bundles, single peak on thermal degradation, removal of lignin-related functional groups and some metal oxide also supported the effectiveness of the AHP-PAA method to isolate TGS cellulose through prehydrolysis, chromophore group deactivation, and delignification reactions.