Paper sludge saccharification for batch and fed-batch production of bacterial cellulose decorated with magnetite for dye decolorization by experimental design

• DOI: 10.1007/s10570-023-05545-6
• Publication Date: 2023-10-31T16:02:11Z
• Authors: Ahmed K. Saleh; Ahmed Salama; Ahmed S. Badawy; Mohamed A. Diab; Hamada El-Gendi
• Keywords: Pulp and paper industry; Materials Science; Biomedical Engineering; Organic chemistry; 02 engineering and technology; Plant Science; FOS: Medical engineering; Nanocellulose: Properties, Production, and Applications; Bacterial Cellulose; Biomaterials; Agricultural and Biological Sciences; Bacterial cellulose; Magnetite; Food science; Engineering; Cellulase; Cellulose; Hydrolysis; Lignin Degradation by Enzymes in Bioremediation; Life Sciences; Materials science; Chemistry; Physical Sciences; Fermentation; Metallurgy; Cellulosic ethanol; 0210 nano-technology; Technologies for Biofuel Production from Biomass

AbstractCellulosic wastes represent a great environmental challenge, with potential conversion to product-added value through microbial fermentation. Currently, bacterial cellulose (BC) is considered a promising natural polymer for multiple applications. However, the high production cost challenges its wide application. Hence, the current study evaluated the applicability of paper sludge as a cost-effective medium for both cellulases and BC production. The local isolate Streptomyces rochei revealed the highest cellulase production titer (about 3 U/mL) at optimized conditions. For BC production, batch and fed-batch fermentation strategies were evaluated using enzymatically hydrolyzed paper sludge. The results asserted the advantage of fed-batch fermentation for advanced BC production (3.10 g/L) over batch fermentation (1.06 g/L) under the same cultivation conditions. The developed BC membranes were characterized through different instrumental analyses, which revealed an increase in fiber diameters and crystallinity under fed-batch fermentation. Furthermore, BC/magnetite (BC/Fe3O4) nanocomposite was developed by an in-situ approach. The newly developed composite was evaluated for dye removal applications, using methyl orange (MO) as a model. The dye removal conditions were optimized through Box Behnken design (BBD), which indicated maximal MO removal (83.5%) at pH 3.0 and BC/Fe3O4 concentration of 0.1 mg/dL after 60 min. Therefore, the current study asserts the good applicability of enzymatically hydrolyzed paper sludge as a medium for cost-effective BC production and the high capacity of BC/magnetite nanocomposite for MO decolorization. The study paves the way for the cost-effective implementation of BC/magnetite nanocomposite for dye removal. Graphical Abstract