Nanobiotechnology and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
Nanobiotechnology and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
Int J Biol Macromol. 2022 Nov 1;220:589-600. doi: 10.1016/j.ijbiomac.2022.08.047. Epub 2022 Aug 11.
Enzyme-mediated isolation of cellulose nanocrystals (CNCs) is a promising environment friendly method with expected lower capital and operating expenditures compared to traditional processes. However, it is still poorly understood. In this study, an endoxylanase was applied as accessory enzyme to assess its potential to increase the selectivity of an endoglucanase during cellulose hydrolysis to isolate CNCs with improved properties. Only combinations of the enzymes with xylanase activity equal to or higher than the endoglucanase activity resulted in CNCs with improved properties (i.e., crystallinity, thermostability, uniformity, suspension stability and aspect ratio). The beneficial effects of the accessory enzyme are related to its hydrolytic (xylan and cellulose hydrolysis) and non-hydrolytic action (swelling of cellulose fibers and fiber porosity) and on the ratio of the enzymes, which in turn allows to tailor the properties of the CNCs. In conclusion, compared to the traditional sulfuric acid hydrolysis method, accessory enzymes help to isolate cellulose nanomaterials with improved and customized (sizes, aspect ratio and morphology) properties that may allow for new applications.
酶介导的纤维素纳米晶体（CNC）分离是一种很有前途的环保方法，与传统工艺相比，预计资本支出和运营支出更低。然而，目前对此方法的了解还很有限。在这项研究中，使用内切木聚糖酶作为辅助酶，评估其在纤维素水解过程中提高内切葡聚糖酶选择性以分离具有改进性能的 CNC 的潜力。只有当酶与木聚糖酶活性等于或高于内切葡聚糖酶活性的组合时，才会得到具有改进性能（即结晶度、热稳定性、均匀性、悬浮稳定性和长径比）的 CNC。辅助酶的有益作用与其水解（木聚糖和纤维素水解）和非水解作用（纤维素纤维溶胀和纤维多孔性）以及酶的比例有关，这反过来又可以调整 CNC 的性能。总之，与传统的硫酸水解法相比，辅助酶有助于分离具有改进和定制（尺寸、长径比和形态）性能的纤维素纳米材料，这可能为新的应用开辟道路。
