Aulitto Martina, Castaldo Rachele, Avolio Roberto, Errico Maria Emanuela, Xu Yong-Quan, Gentile Gennaro, Contursi Patrizia
Department of Biology, Università degli Studi di Napoli Federico II, 80138 Napoli, Italy.
Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Polymers (Basel). 2023 Feb 23;15(5):1115. doi: 10.3390/polym15051115.
Nanostructured cellulose (NC) represents an emerging sustainable biomaterial for diverse biotechnological applications; however, its production requires hazardous chemicals that render the process ecologically unfriendly. Using commercial plant-derived cellulose, an innovative strategy for NC production based on the combination of mechanical and enzymatic approaches was proposed as a sustainable alternative to conventional chemical procedures. After ball milling, the average length of the fibers was reduced by one order of magnitude (down to 10-20 μm) and the crystallinity index decreased from 0.54 to 0.07-0.18. Moreover, a 60 min ball milling pre-treatment followed by 3 h Cellic Ctec2 enzymatic hydrolysis led to NC production (15% yield). Analysis of the structural features of NC obtained by the mechano-enzymatic process revealed that the diameters of the obtained cellulose fibrils and particles were in the range of 200-500 nm and approximately 50 nm, respectively. Interestingly, the film-forming property on polyethylene (coating ≅ 2 μm thickness) was successfully demonstrated and a significant reduction (18%) of the oxygen transmission rate was obtained. Altogether, these findings demonstrated that nanostructured cellulose could be successfully produced using a novel, cheap, and rapid 2-step physico-enzymatic process that provides a potential green and sustainable route that could be exploitable in future biorefineries.
纳米结构纤维素（NC）是一种新兴的可持续生物材料，可用于多种生物技术应用；然而，其生产需要使用危险化学品，这使得该过程对生态环境不友好。基于商业植物源纤维素，提出了一种将机械和酶法相结合的创新型NC生产策略，作为传统化学方法的可持续替代方案。球磨后，纤维的平均长度降低了一个数量级（降至10-20μm），结晶度指数从0.54降至0.07-0.18。此外，先进行60分钟的球磨预处理，然后进行3小时的Cellic Ctec2酶水解，可生产出NC（产率为15%）。对通过机械酶法获得的NC的结构特征进行分析发现，所获得的纤维素原纤维和颗粒的直径分别在200-500nm和约50nm范围内。有趣的是，成功证明了在聚乙烯上的成膜性能（涂层厚度约为2μm），并使氧气透过率显著降低（18%）。总之，这些发现表明，使用一种新型、廉价且快速的两步物理酶法能够成功生产纳米结构纤维素，该方法提供了一条潜在的绿色可持续途径，可在未来的生物精炼厂中加以利用。
