Standard powder cellulose from Sigma, microcrystalline cellulose or cotton linters have granular structure and thus the particle size can be directly determined using SEM. However, the fibrous structure of bacterial cellulose powder has irregular morphology and thus the particle size need to be determined via a different approach. Moreover because the powder shows poor flowability, the test was performed using wet method in which the cellulose was dispersed in distilled water. Bacterial cellulose has many hydroxyl groups, and these groups interact with water to form hydrogen bond; thus, the bacterial cellulose has a tendency to swell. Hence, for accurately determining the particle size, the value acquired by this method should consider the swelling power of the cellulose fibres.