STRUCTURAL CHARACTERIZATION AND SUGAR RECOVERY FROM SPENT MUSHROOM COMPOST AND SAWDUST VIA ACID PRETREATMENTS FOR POTENTIAL LACTIC ACID BIOCONVERSION

Agricultural residues, such as spent mushroom compost (SMC) and sawdust (SD), are promising lignocellulosic biomasses for sustainable biochemical production. This study evaluates the structural modification and sugar recovery efficiency from SMC derived from Pleurotus and Schizophyllum species, as well as sawdust, following pretreatment with sulfuric acid and lactic acid. Structural changes were assessed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), while sugar content was quantified via high-performance liquid chromatography (HPLC). Pretreatments were conducted at 105 °C for 60, 120, and 180 minutes. Sulfuric acid was more effective than lactic acid in enhancing cellulose accessibility and removing hemicelluloses and lignin. The results showed that the highest cellulose content (61.63%) was observed in sulfuric acid-treated SMCS at 180 minutes, while the maximum total sugar yield (80%) was obtained from Pleurotus SMC. These findings highlight the potential of acid-pretreated SMC and sawdust as viable substrates for lactic acid bioconversion, laying the groundwork for optimizing pretreatment strategies in biorefineries.