A by-product of the mushroom industry, spent mushroom substrate (SMS) is primarily made of lignocellulosic agricultural waste. SMS contains cellulose (38-46.6%), lignin (25-34.5%), and hemicellulose (19-27.7%) and is nutrient-rich. The primary objectives of this study included the characterization of SMS, analysis of lignocellulosic content prior to and following pre-treatment, analysis of the effects of various NaOH concentrations with varying molarities (1.0 to 5.0 Molar), and analysis of surface morphology using a scanning electron microscope (SEM). The result that comparison between untreated and treated sample The result for untreated are contain high amount of lignin from 23.85% to 27.39% and for treated are amount reduce from 20.6% to 23.85%. The difference of NaOH concentration from 1.0 to 5.0 Molar, so the best pre-treatment is alkaline pre-treatment from 1.0 to 3.0 M are the best concentration to treat SMS sample from alkaline pre-treatment and proved sodium hydroxide pre-treatment as an effective method to reduce the hemicellulose and lignin contents. Images clearly showed how the pre-treatment could alter the biomass's structural makeup and distort it, increasing the surface area that was open to enzymatic attack. The pre-treated SMS's surface had numerous sporadic pores and cracks. The study's findings demonstrated that SMS from the P. sajor-caju species has the potential to provide a new source of glucose for bioethanol production.
