Department of Systems and Synthetic Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.
Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.
Carbohydr Polym. 2021 Mar 15;256:117511. doi: 10.1016/j.carbpol.2020.117511. Epub 2020 Dec 15.
A combined enzymatic treatment/acid hydrolysis technique was utilized to synthesize cellulose nanocrystals (CNCs) from sugar beet pulp. CNCs were functionalized with magnetite nanoparticles and dopamine making a versatile nano-carrier (DA/FeONPs@CNCs) for covalent enzyme immobilization. Oxygene/amine functionalities, high magnetization value, and specific surface area of DA/FeONPs@CNCs made it a reusable and green candidate for conjugation to hydrolytic enzyme cocktails (three cellulases, two hemicellulases, and their combinations) to prepare an innovative and practical nano-biocatalyst for biomass conversion. The conjugated enzymes showed an enhanced optimum temperature (∼ 10 °C), improved thermal stability, and shifted optimum pH toward alkaline pHs. Covalent attachment could successfully suppress the enzyme leaching and provide easy recovery/reuse of the nano-biocatalyst up to 10 cycles, with > 50% of initial activity. Application of the nano-biocatalyst in hydrolysis of rice straw and sugar beet pulp showed an increase (20-76%) in the yield of fermentable sugars compared to the free enzyme cocktails.
采用酶处理/酸水解联合技术，从糖甜菜浆中制备纤维素纳米晶体（CNC）。通过多巴胺对 CNC 进行功能化，使其表面修饰上磁性纳米颗粒，形成多功能纳米载体（DA/FeONPs@CNCs），用于共价酶固定化。DA/FeONPs@CNCs 具有含氧/胺功能基团、高磁化值和比表面积，是一种可重复使用和绿色的酶偶联候选物，可与水解酶鸡尾酒（三种纤维素酶、两种半纤维素酶及其组合）偶联，制备用于生物质转化的新型实用纳米生物催化剂。固定化酶显示出增强的最适温度（约 10°C）、提高的热稳定性和向碱性 pH 值的最适 pH 值偏移。共价键合可以成功抑制酶的浸出，并提供纳米生物催化剂的易于回收/再利用，可达 10 个循环，初始活性保持在 50%以上。纳米生物催化剂在水稻秸秆和糖甜菜浆水解中的应用，与游离酶鸡尾酒相比，可提高可发酵糖的产率（提高 20-76%）。
