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- Feng, Nianjie, et al.
(författare)
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Changes in chemical structures of wheat straw auto-hydrolysis lignin by 3-hydroxyanthranilic acid as a laccase mediator
- 2019
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Ingår i: International Journal of Biological Macromolecules. - : ELSEVIER SCIENCE BV. - 0141-8130 .- 1879-0003. ; 122, s. 210-215
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Tidskriftsartikel (refereegranskat)abstract
- 3-Hydroxyanthranilic acid (3-HAA), as a potential natural laccase mediator, was shown to mediate the oxidation of non-phenolic lignin subunits. The problem of cost and toxicity of artificial mediators could be solved to some extent by a further study about the detailed changes of lignin chemistry structures in laccase 3-HAA system (LHS). In this work, wheat straw auto-hydrolysis lignin (AL) was prepared. Oxidations of AL by LHS and laccase 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) system were then investigated, respectively. Various structural changes of AL during the oxidation were characterized by different methods including phenolic hydroxyl group determination, nitrobenzene oxidation, ozonation, gel permeation chromatography, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy. The changes in AL chemical structures were found in LHS, including unit removal, bond cleavage and biopolymerization. Compared to laccase ABTS system, a selective removal of guaiacyl-type lignin in LHS was observed, based on the results of nitrobenzene oxidation and 2D NMR analysis. The selective removal of guaiacyl-type lignin was due to improved aromatic ring cleavage and weaken lignin biopolymerization. The selectivity of guaiacyl-type lignin removal in LHS plays an important role, especially for improving bioconversion efficiency of laccase for guaiacyl-rich lignocellulosic biomass.
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| 2. |
- Feng, Nianjie, et al.
(författare)
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Improving Degradation Ability Toward Wheat Straw Chemical Composition by Co-Cultivation of Pycnoporus sanguineus with Candida tropicalis
- 2015
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Ingår i: Journal of Biobased Materials and Bioenergy. - : American Scientific Publishers. - 1556-6560 .- 1556-6579. ; 9:6, s. 567-571
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Tidskriftsartikel (refereegranskat)abstract
- It is important for lignocellulosic bioconversion of wheat straw to be intensified by co-cultivation of Pycnoporus sanguineus with Candida tropicalis. The biodegradation properties, involving the enzymes composition and their activities, fibrous tissue morphologies, and chemical composition of co-cultivation, were studied. The co-cultivation obviously improved enzymes composition and enhanced carboxymethyl cellulase, xylanase and laccase activities. The co-cultivation increased the porosity of fibrous tissue in wheat straw. The co-cultivation is presented an advantageous performance in the aspects of lignin and carbohydrate degradation than the cultivation of P. sanguineus alone. The degradation process of the chemical composition in wheat straw by the co-cultivation can be divided into the first rapid phase and the following slow degradation one. The co-cultivation of P sanguineus with C. tropicalis increased the delignification by 15.2% in the rapid phase and the carbohydrate degradation ratio by 61.5% in the slow phase. The above intensifying degradation ability were resulted from the combination improvement of enzymes composition, their activities and fibrous tissue morphologies.
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