<p>The objective of this study is to assess the most commonly applied mechanical techniques with a concentration on their effects on the physical properties of cellulose micro and nanofibers from sugarcane bagasse by consuming acid and alkaline hydrolysis to remove non-cellulosic components. In this research, a sample produced at 150 °C for 1 h with a concentration of 1 M acid exhibited minimal fiber damage. X-ray diffraction (XRD) analysis confirmed accurate microcellulose extraction. Brunauer-Emmett-Teller (BET) analysis revealed a specific surface area of approximately 3 m²/g and pore sizes of approximately 13 nm, highlighting microcellulose’s structural attributes. Chemical composition analysis demonstrated an 88.7% lignin volume reduction while retaining 92.5% of extracted cellulose fibers. Furthermore, scanning electron microscopy (SEM) showed initial micrometer-scale fiber dimensions with a wide distribution of microfiber diameters. As the extraction process continued, the distribution narrowed, reducing the average microfiber diameter. Among the mechanical methods employed, the ultrasonic treatment proved the most effective in reducing microfiber diameter, with homogenization and Ultra-Turrax showing varying degrees of influence. Extended ultrasonic treatment durations efficiently disentangle and distribute microfibers throughout the composite structure, reducing microfiber diameter and enhancing uniformity. A 3-h ultrasonic exposure efficiently reduced particle size to 30 nm, establishing the optimal duration.</p> Graphical Abstract <p></p>