ABSTRACT Bacterial cellulose (BC) has emerged as a promising biomaterial due to its purity, biocompatibility, and tunable physicochemical and mechanical properties. However, its large‐scale production and subsequent purification remain a challenge for the applications. Alternative methods to produce BC include symbiotic cultures of bacteria and yeast (SCOBY) with a fertilizer medium. In this work, the bleaching of BC membranes with commercial sodium hypochlorite (NaClO, 5% w/v) followed by neutralization with sodium thiosulfate (Na 2 S 2 O 3 ) was studied and evaluated with respect to yield, morphology, crystallinity, elemental composition, and colorimetric properties. While the NaClO efficiently removed microbial debris and pigments, it also produced progressively whiter and structurally refined membranes at a moderate concentration of 2% v/v. Despite an increase in whiteness, higher NaClO contents led to significant mass loss, fibril disruption, and oxidative degradation. On the other hand, upon neutralization with Na 2 S 2 O 3 , the residual chlorine was quenched, leaving minimal sulfur traces, without altering the BC chemistry or crystallinity. Colorimetry confirmed that, when combined, the bleaching and neutralization result in optimal whitening and reduced color saturation. The findings are indicative that moderate bleaching followed by sodium thiosulfate neutralization provides a simple and effective purification strategy for membrane whiteness and safety for applications.
Gomez‐Maldonado et al. (Thu,) studied this question.