机械力化学效应对麦草浆重组木聚糖酶生物漂白的影响

利用机械力化学作用,以提高木聚糖酶预处理效果。论文研究了磨浆对重组木聚糖酶预处理效果的影响;磨浆前后重组木聚糖酶预处理对浆料漂白性能的影响。研究结果表明:采用机械力化学作用酶处理时比较适合的磨浆时间为5 min,打浆度在30 oSR左右,在酶用量为5 IU/g时,脱木素率达到29.7%,与磨浆前酶处理相比,脱木素率提高了34.4%;磨浆前后的浆料经过重组木聚糖酶预处理,在后续漂白时漂至与对照浆相近白度时(72.6%ISO),分别节省了50%和57.1%用氯量,大大减轻了漂白废水对环境的污染;通过磨浆前后酶处理液高效液相色谱分析、浆料结晶度测定以及扫描电镜的观察,从理论上证实了重组木聚糖酶在助漂时的机械力化学效应,并为它的广泛应用提供了理论依据。     

pH值对木聚糖酶预处理麦草浆的影响

利用木聚糖酶对麦草浆进行预处理,可有效降低后续漂白时的有效氯用量.在不同的pH值影响下,酶与底物均有不同的解离状态,最终影响酶活力.结果表明:经过不同pH值下木聚糖酶的预处理,综合考虑纸浆的白度、卡伯值、强度等因素,最适的木聚糖酶预处理麦草浆的pH值为6.0.     

漆酶与木聚糖酶预处理对稻草蒸煮性能影响的比较

利用木聚糖酶和漆酶对稻草进行预处理,以改善后续的蒸煮性能。研究了不同酶用量对酶预处理效果的影响;同时比较了两种酶预处理对蒸煮性能的影响。结果表明木聚糖酶和漆酶对稻草预处理均能达到改善纸浆性能的目的。较佳的酶用量分别为20IU/g和30IU/g。在提高蒸煮得率、浆料强度方面漆酶优于木聚糖酶,与未处理和木聚糖酶化学浆相比实际得率分别提高13.11%和8.79%;裂断长提高34.2%和5.54%;耐破指数提高23.81%和7.22%;撕裂指数提高78.59%和3.26%。木聚糖酶预处理对改善浆料白度方面则优于漆酶,与未处理浆和漆酶生物化学浆相比分别提高5.3%和0.6%(SBD)。     

芦苇烧碱-蒽醌浆生物漂白的研究

对芦苇烧碱-蒽醌浆进行漆酶/介体体系脱木素处理结合过氧化氢漂序进行漂白。结果表明,分别利用三种介体HBT、VIO和NHA辅助漆酶脱木素,导致浆的白度均有不同程度的降低,降低的幅度与介体种类和用量有关。在相同浓度时,浆白度的降低幅度随介体的氧化还原电势的增大而增大。根据过氧化氢漂白的结果,可以认为LMS-QP最佳处理条件为使用介体NHA,用量为0.5%,漂白时间为2 h。对用2%VIO为介体脱木素后的浆残余木素分析表明,经过漆酶/介体体系处理浆料,浆残余木素中的羰基含量相对提高。     

打浆前后酶处理对草浆性能的影响

用木聚糖酶处理漂白草浆能改善浆料性能。采用产自黑曲霉的木聚糖酶处理打浆前和打浆后的浆料 ,发现浆料的滤水性、白度和强度均得到提高。酶处理最适合的条件是 :酶用量 3～ 5IU/g ,处理温度 45℃ ,处理时间 60min ,浆浓 5 %。轻微打浆后再进行酶处理比打浆前酶处理的效果好     

木聚糖酶预处理对NaOH-AQ法麦草浆H_2O_2漂白效果的影响

探讨了木聚糖酶预处理对麦草化学浆 H2 O2 漂白可漂性等的影响。结果表明 :与对照浆漂至相近白度 ,木聚糖酶预处理后可节省 H2 O2 用量 4 0 %以上 ,且浆的强度变化不大 ;酶预处理还可以改善 H2 O2 漂后浆的滤水性能 ,提高漂白浆的白度稳定性。     

木聚糖酶预处理对NaOH—AQ法麦草浆H2O2漂白效果的影响

探讨了木聚糖酶预处理对麦草化学浆Ｈ２Ｏ２漂白可漂性等的影响。结果表明：与对照浆漂至相近白度，木聚糖酶预自理后可节省Ｈ２Ｏ２用量４０％以上，且浆的强度变化不大；酶预处理还可以改善Ｈ２Ｏ２漂后浆的滤水性能，提高漂白浆的白度稳定性。     

漆酶对未漂马尾松磨木浆的酶法改性

利用NS51002和NS51003漆酶/介体分别对马尾松未漂磨石磨木浆(GP)进行生物酶处理及后续的H2O2漂白,并对酶处理浆漂白前后的白度和强度性能进行测定。研究结果表明,利用漆酶NS51003处理马尾松未漂GP,可有效提高纸浆的白度及强度性能,而且酶处理后纸浆具有更好的可漂性,并且经过H2O2漂白后的酶处理浆亦具有更高的白度和更好的强度性能;而漆酶NS51002漆酶/介体对纸浆的改性效果甚微。     

纤维素/半纤维素酶配合漆酶预处理马尾松未漂磨石磨木浆的研究

分别用半纤维素酶PulpzymeHC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理,然后再进行NS51003漆酶/介体系统生物酶处理及后续的H2O2漂白,并对酶处理浆在H2O2漂白前后白度和强度性能进行测定。研究结果表明,利用半纤维素酶PulpzymeHC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理,可有效提高漆酶NS51003处理马尾松未漂GP的效率,更加有效的提高纸浆的白度及强度性能,而且适当的预处理可使纸浆具有更好的可漂性,从而使H2O2漂白后的酶处理浆具有更高的白度和更好的强度性能。     

纤维素／半纤维素酶配合漆酶预处理马尾松未漂磨石磨木浆的研究

分别用半纤维素酶Pulpzyme HC、纤维素酶Novozym 476对马尾松未漂磨石磨木浆(GP)进行预处理，然后再进行NS51003漆酶／介体系统生物酶处理及后续的H2O2漂白，并对酶处理浆在H2O2漂白前后白度和强度性能进行测定。研究结果表明，利用半纤维素酶Pulpzyme HC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理，可有效提高漆酶NS51003处理马尾松未漂GP的效率，更加有效的提高纸浆的白度及强度性能，而且适当的预处理可使纸浆具有更好的可漂性，从而使H2O2漂白后的酶处理浆具有更高的白度和更好的强度性能。     

高纯耐热耐碱木聚糖酶预处理对杨木KP浆漂白特性的影响

研究了耐热耐碱木聚糖酶X对杨木硫酸盐浆预处理的选择性及其对无元素氯(ECF)漂白特性的影响。结果表明:该木聚糖酶预处理具有高的助漂选择性,预处理对纸浆的得率及黏度影响不大;该木聚糖酶对温度及pH的适应范围较广,在温度为75～80℃、pH 8.0～9.5范围内都可以发挥有效的助漂作用,尤其在温度80℃、pH 8.0、酶用量2 IU/g的条件下更能发挥酶效;耐热耐碱木聚糖酶X预处理可减少漂白ClO2用量,当达到对照浆相同白度(90%ISO)时可减少D0段26%～27%的ClO2用量(相当于总用氯量的16%)。     

Study on Direct Delignification with Laccase/Xylanase System

Abstract

Direct degradation of lignin with laccase/xylanase system (LXS) instead of the expensive laccase/mediator system (LMS) was investigated. The optimal treatment conditions with LXS were determined. The lignin degrading ability and the physical properties of enzyme treated pulps were compared between LXS and LMS. The results indicated that the optimum treatment conditions of pine kraft pulp with LXS were pH 4.2, temperature 45°, pulp consistency 3%, time 3 h, laccase dosage 10 IU/g. LXS has as strong an ability to delignify with good selectivity as LMS. The strength of pulp was obviously enhanced by LMS treatment to the same extent as LMX when compared with the control at 30 ⁰SR. Thus, LXS can entirely replace expensive and complicated LMS for bio-delignification application.     

Assessing the use of xylanase and laccases in biobleaching stages of a TCF sequence for flax pulp

BACKGROUND: In this study, two different laccases were used in combination with various mediators as biobleaching agents in a TCF sequence for flax fibre and pulp. Thus, non‐commercial laccase from Pycnoporus cinnabarinus (PcL) was used with the synthetic mediator violuric acid (VA) or the natural mediator syringaldehyde (SA), and commercial laccase from Myceliophthora thermophila (MtL) was used with the natural mediator methyl syringate (MS). Each laccase–mediator treatment was used in the following TCF bleaching sequence: LQPo (Q denoting a chelating stage and Po a pressurized alkaline peroxide treatment). Also, a xylanase pretreatment was carried out for first time here to assess its effect on flax fibre. Pulp (kappa number, viscosity and brightness) and effluent properties (COD, colour, residual activity and toxicity) were determined after each bleaching stage. The hexenuronic acid (HexA) content of the pulp was also determined to assess its integrity. RESULTS: The best L stage was PcL + VA, which provided a final brightness and kappa number of 81% ISO and 1.3, respectively. Using a xylanase pretreatment was found to efficiently remove HexA and enhance delignification by laccase (final kappa number 0.7). CONCLUSIONS: These results warrant upscaling any of these biobleaching sequences for flax pulp as they provide environmentally sustainable flax fibre with a high cellulose content and brightness above 80% ISO. Copyright © 2011 Society of Chemical Industry     

Effect of xylanase on ozone bleaching kinetics and properties of Eucalyptus kraft pulp

Environmental pressure has led the pulp and paper industry to develop new technologies in order to reduce or suppress the presence of various pollutants in effluents from bleaching plants. One of the choices for this purpose is enzyme‐based biotechnology. This study deals with the effect of using a xylanase‐based enzymatic pretreatment, in a TCF (Totally Chlorine Free) sequence, on the properties of the resulting paper pulps. The hexenuronic acid content in the pulp and the physical properties of the paper were also studied. The performance of the xylanase was analysed through kinetic studies on ozone bleaching. The enzymatic pretreatment results in easier bleaching and delignification of the pulp, causing a bleach‐boosting effect. The decreased consumption of reagent is related to a decreased content of hexenuronic groups. The physical properties of the treated pulp are similar to those of untreated pulps. Cellulose degradation, delignification and chromophores' removal show first‐order kinetics. Enzyme pretreatment leads to differences between the kinetic constants of cellulose degradation and chromophores' removal, due to an increased accessibility to bleaching agents. The xylanase treatment leads to a lower floor kappa number (IK_∞) during the ozone stage. Copyright © 2003 Society of Chemical Industry     

漆酶和聚木糖酶协同漂白蔗渣硫酸盐浆的研究

进行了蔗渣硫酸盐浆漆酶 /介体 (LMS)生物漂白的研究 ,分析了漆酶 /介体体系和聚木糖酶在漂白流程中作为前后漂段或在同一段中同时使用对漂白效果的影响。漆酶 /介体体系与聚木糖酶同时或前后处理蔗渣硫酸盐浆 ,在一定程度上提高了纸浆的漂终白度和强度 ,说明生物漂白改善了漂白选择性     

木聚糖酶在麦草碱法化机浆中的应用研究

对木聚糖酶预处理的麦草碱法化学机械制浆与漂白过程中木聚糖酶处理的效果进行了研究。结果表明,在制浆与漂白前酶预处理段较佳的木聚糖酶用量分别为 15 IU/g 和 12 IU/g,酶预处理时间同为 120 min。利用木聚糖酶预处理与 H2O2漂白相结合的 XP5aP5a 多段漂白程序,可以获得 74.6%ISO白度的麦草生物化机浆。     

麦草生物化机浆的木聚糖酶漂白

探讨了在由PhanerochaetechrysosporiumME446麦草上固态发酵制得的木聚糖粗酶对麦草生物化机浆漂白效果的改善作用,并对其预处理工艺进行了优化。实验结果表明,当木聚糖酶用量为15IU/g,浆浓15%,处理3h后,麦草生物化机浆的白度可达到66.1%ISO。文章还对木聚糖酶处理前后的麦草化机浆纤维进行了扫描电镜的观察。