University of Belgrade-Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
Institute for Multidisciplinary Studies, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
Int J Biol Macromol. 2021 Jun 30;181:1072-1080. doi: 10.1016/j.ijbiomac.2021.04.115. Epub 2021 Apr 20.
High amounts of toxic textile dyes are released into the environment due to coloring and wastewaters treatment processes' inefficiency. To remove dyes from the environment and wastewaters, researchers focused on applying immobilized enzymes due to mild reaction conditions and enzyme nontoxicity. Laccases are oxidases with wide substrate specificity, capable of degradation of many different dye types. Laccase from Streptomyces cyaneus was expressed on the surface of Saccharomyces cerevisiae EBY100 cells. The specific activity of surface-displayed laccase was increased by toluene-induced lysis to 3.1 U/g of cell walls. For cell wall laccase immobilization within hydrogel beads, alginate was modified by dopamine using periodate oxidation and reductive amination and characterized by UV-Vis, FTIR, and NMR spectroscopy. Cell wall laccase was immobilized within alginate and dopamine-alginate beads additionally cross-linked by oxygen and laccase. The immobilized enzyme's specific activity was two times higher using dopamine-alginate compared to native alginate beads, and immobilization yield increased 16 times. Cell wall laccase immobilized within dopamine-alginate beads decolorized Amido Black 10B, Reactive Black 5, Evans Blue, and Remazol Brilliant Blue with 100% efficiency and after ten rounds of multiple-use retained decolorization efficiency of 90% with Evans Blue and 61% with Amido Black.
由于染色和废水处理过程效率低下，大量有毒纺织染料被释放到环境中。为了从环境和废水中去除染料，研究人员专注于应用固定化酶，因为其反应条件温和且酶无毒性。漆酶具有广泛的底物特异性，是一种氧化酶，能够降解许多不同类型的染料。青霉菌来源的漆酶在酿酒酵母 EBY100 细胞表面表达。甲苯诱导裂解使表面展示漆酶的比活提高到 3.1 U/g 细胞壁。为了在水凝胶珠内固定细胞壁漆酶，使用高碘酸盐氧化和还原胺化对海藻酸钠进行多巴胺修饰，并通过紫外-可见、傅里叶变换红外和核磁共振波谱进行表征。细胞壁漆酶通过氧和漆酶进一步交联固定在海藻酸钠和多巴胺-海藻酸钠珠内。与天然海藻酸钠珠相比，使用多巴胺-海藻酸钠固定化酶的比活提高了两倍，固定化产率提高了 16 倍。固定在多巴胺-海藻酸钠珠内的细胞壁漆酶能 100%有效地脱色艳蓝 10B、活性黑 5、埃文斯蓝和丽春红，并且经过十轮多次使用后，埃文斯蓝和艳蓝的脱色效率分别保持 90%和 61%。
