Utilization of bacterial nanocellulose (BNC) for large-scale applications is restricted by low productivity in static cultures and by the high cost of the medium. Fiber sludge, a waste stream from pulp and paper mills, was enzymatically hydrolyzed to sugar, which was used for the production of BNC by the submerged cultivation of Komagataeibacter xylinus. Compared with a synthetic glucose-based medium, the productivity of purified BNC from the fiber sludge hydrolysate using shake-flasks was enhanced from 0.11 to 0.17 g/(L x d), although the average viscometric degree of polymerization (DPv) decreased from 6760 to 6050. The cultivation conditions used in stirred-tank reactors (STRs), including the stirring speed, the airflow, and the pH, were also investigated. Using STRs, the BNC productivity in fiber-sludge medium was increased to 0.32 g/(L x d) and the DPv was increased to 6650. BNC produced from the fiber sludge hydrolysate was used as an additive in papermaking based on the chemithermomechanical pulp (CTMP) of birch. The introduction of BNC resulted in a significant enhancement of the mechanical strength of the paper sheets. With 10% (w/w) BNC in the CTMP/BNC mixture, the tear resistance was enhanced by 140%. SEM images showed that the BNC cross-linked and covered the surface of the CTMP fibers, resulting in enhanced mechanical strength.
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机译:细菌纳米纤维素(BNC)在大规模应用中的使用受到静态培养物中生产率低和培养基成本高的限制。纤维污泥(制浆造纸厂的废料流)被酶水解为糖,糖通过木薯Komagataeibacter xylinus的深层培养被用于生产BNC。与基于葡萄糖的合成培养基相比,使用摇瓶从纤维污泥水解产物中纯化的BNC的产率从0.11提高至0.17 g /(L xd),尽管平均粘度聚合度(DPv)从6760降低至0.16 g /(L xd)。 6050.还研究了搅拌釜反应器(STRs)中使用的培养条件,包括搅拌速度,气流和pH值。使用STR,纤维污泥介质中的BNC生产率提高到0.32 g /(L xd),DPv增加到6650。由纤维污泥水解产物产生的BNC被用作造纸中的添加剂,化学造纸机械浆(CTMP) )的桦木。 BNC的引入大大提高了纸张的机械强度。在CTMP / BNC混合物中使用10%(w / w)BNC时,抗撕裂性提高了140%。 SEM图像表明BNC交联并覆盖了CTMP纤维的表面,从而提高了机械强度。
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