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This study investigates the sulfuric acid hydrolysis process to improve the efficiency of paper waste sludge (PWS) hydrolysis in a paper recycling plant. The Response Surface Methodology (RSM) was used to evaluate the influence of factors, including liquid-to-solid ratio, acid concentration, temperature, and time on the hydrolysis process. The optimal conditions for hydrolysis were determined to be a solid-to-liquid ratio of 1/30.15, an acid concentration of 8.17 wt%, at a temperature of 91.31 ?, and a reaction time of 6.15 h, which yielded the highest sugar content of 11.12 g.L-1 (with the hydrolysis efficiency of 61.4 %). The resulting sugar solution was then fermented by Acetobacter xylinum bacteria to produce bacterial cellulose (BC) layers. This study addresses the environmental organic pollution caused by PWS and transforms it into a more valuable form with high carbon content and purity, such as BC.

This study aimed to produce bacterial cellulose from paper waste sludge (PWS) as a method of utilizing the cellulose source from the remaining pulp in the material. Initially, PWS was hydrolyzed by sulfuric acid to create an enriched-reducing sugar hydrolysate. One-factor experiments were conducted with a fixed amount of PWS (5 g) to investigate the influence of hydrolysis conditions, including water, sulfuric acid addition, temperature, and retention time, on the production yield of reducing sugars. Based on these results, the Box-Behnken model was designed to optimize the hydrolysis reaction. The optimal hydrolysis conditions were 10 ml/g of the sulfuric acid solution (30.9%) at 105.5 °C for 90 min of retention time 0.81 (gGE/g PWS), corresponding to a conversion yield of 40.5%). Subsequently, 100 ml of the filtered and neutralized PWS hydrolysate was used as the culture to produce the bacterial cellulose (BC) using Acetobacter xylinum, which produced 12 g/L of bacterial cellulose. The conversion yield of bacterial cellulose calculated as the ratio of the weight of produced bacterial cellulose to that of cellulose in PWS reached 33.3%. The structure of the obtained BC was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) to indicate the formation of nano-cellulose fiber networks. This research proposed a combined method to convert paper waste sludge into bacterial cellulose, demonstrating the potential for waste utilization and sustainable production of paper industries for added-value products.