Increasing enzymatic saccharification of saccharide polymers in lignocellulosic biomass with subcritical water treatment

Oil palm trunk (OPT) is one of the wastes from logging oil palm trees that are no longer productive. OPT contains cellulose, hemicellulose, and lignin, which can be hydrolyzed to produce fermentable sugar and further converted into biofuel and value-added chemicals for food ingredients such as xylitol, lactic acid, dietary fiber, prebiotics, and compounds for food packaging. The OPT pretreatment aims to break down the recalcitrant by breaking down the lignin bonds to increase the efficiency of enzymatic hydrolysis of polysaccharides. This study aimed to apply the pretreatment with the subcritical water (SCW) method at 170℃, 400 psi, for 20 mins on OPT samples and confirm the achievement of the delignification objective in the samples by conducting chemical component analysis and observing changes in the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) spectra of raw OPT samples and which has been given pretreatment and enzymatic saccharification analysis. The findings from the study revealed that pretreatment with the SCW method reduced the levels of lignin and hemicellulose by 30.43% and 42.53%, respectively, while the percentage of cellulose increased by 50.34%. XRD and FTIR spectroscopy analysis also revealed the change in the structure of the pretreated OPT. The total reducing sugar of the OPT samples after enzymatic hydrolysis increased in the pretreated sample, which was 11 g/g, compared to the raw OPT, which was 8 g/g. SCW pretreatment method at 170°C, 400 psi, for 20 mins was able to give a delignification effect and increase saccharification in enzymatic hydrolysis of OPT.