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Cañas AI Alcalde M Plou F Martínez MJ Martínez AT Camarero S 《Environmental science & technology》2007,41(8):2964-2971
Efficient transformation of several polycyclic aromatic hydrocarbons (PAHs) was obtained using a fungal laccase in the presence of phenolic compounds related to those formed in nature during the turnover of lignin and humus. The effect of these natural mediators, namely vanillin, acetovanillone, acetosyringone, syringaldehyde, 2,4,6-trimethylphenol, p-coumaric acid, ferulic acid, and sinapic acid, was compared with that of synthetic mediators such as 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 1-hydroxybenzotriazole (HBT). Anthracene was significantly degraded by laccase in the absence of mediators, whereas benzo[a]pyrene and pyrene were weakly transformed (less than 15% after 24 h). Vanillin, acetovanillone, 2,4,6-trimethylphenol, and, above all, p-coumaric acid strongly promoted the removal of PAHs by laccase. 9,10-Anthraquinone was the main product detected from anthracene oxidation by all the laccase-mediator systems. The yield of anthraquinone formed was directly correlated with the amount of p-coumaric acid used. This compound resulted in a better laccase mediator than ABTS and close similarity to HBT, attaining 95% removal of anthracene and benzo[a]pyrene and around 50% of pyrene within 24 h. Benzo[a]pyrene 1,6-, 3,6-, and 6,12-quinones were produced during benzo[a]pyrene oxidation with laccase and p-coumaric acid, HBT, or ABTS as mediators, although use of the latter mediator gave further oxidation products that were not produced by the two other systems. 相似文献
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Gutiérrez A Del Rio JC Ibarra D Rencoret J Romero J Speranza M Camarero S Martínez MJ Martínez AT 《Environmental science & technology》2006,40(10):3416-3422
Free and conjugated sterols are among the main compounds responsible for pitch deposition in the manufacture of wood chemical pulps, making difficult the implementation of totally chlorine free bleaching (TCF) and closure of bleach plant circuits. In this work, the suitability of oxidative enzymes in efficiently removing sterols from eucalypt pulps is revealed. The enzymatic treatment was applied as an additional stage of an industrial-type TCF sequence for bleaching eucalypt kraft pulp. The pulp obtained after oxygen delignification was treated with a high-redox potential and thermostable fungal laccase using 1-hydroxybenzotriazole as an enzyme mediator. This pulp was further submitted to chelation and peroxide stages and compared with a control TCF pulp obtained using chemical reagents. The composition of the lipophilic extractives in the pulps and the corresponding liquids after the different stages was analyzed by gas chromatography and gas chromatography--mass spectrometry. Free sitosterol and sitosterol esters and glucosides, the major lipophilic compounds in eucalypt pulps, were completely removed during the laccase-mediator treatment. Only some intermediate products from sitosterol oxidation remained after the laccase stage, as well as in the final pulp. Pulp brightness was also improved due to the simultaneous removal of lignin by the laccase-mediator treatment. 相似文献
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采用响应面分析法对漆酶介体体系(LMS)处理NaOH-AQ玉米秆浆的三个主要工艺参数(漆酶用量,介体HBT用量和处理时间)进行了优化研究,并考察了LMS预处理对后续漂白的影响。结果表明LMS处理NaOH-AQ玉米秆浆的最优工艺条件:漆酶用量27.7IU/g,HBT1%,处理时间4.2h。在此优化条件下,对比了有/无LMS预处理漂白浆的性质,结果表明:在达到相同白度(约74%ISO)时,有LMS预处理可以节省约83%的H2O2用量;在后续H2O2用量(2%)相同时,LMS预处理过的纸浆白度可提高10.44%ISO,卡伯值降低2,并保持了较好的强度性能。 相似文献
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采用气相色谱-质谱联用(GC-MS)对APMP废液中酚类物质进行鉴别,同时对不同方式处理的OCC纸浆进行纤维性能分析和成纸物理性能检测。GC-MS分析表明,APMP废液中含有3种酚类物质——对-甲氧基-苯酚、紫丁香醇和松柏醇,并且在其与漆酶共同处理OCC纸浆过程中这些酚类物质参与反应;模型物凝胶色谱(GPC)分析表明,漆酶处理后小分子酚类物质发生了自由基缩合,产物聚合;纤维形态和表面电镜分析表明,聚合的小分子酚类物质以缩合木素的形式迁移到纤维表面,增加纤维表面木素含量,从而提高成纸强度特别是湿环压强度。 相似文献
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本实验以烧碱-蒽醌法蔗渣浆为原料,选用3种漆酶漂白的天然介体和1种合成介体,对蔗渣浆进行LQP三段处理,以此来考察不同介体及用量对处理后纸浆白度、强度及漂后废水COD污染负荷的影响。经过研究可知,纸浆经LQP三段处理,其白度明显得到改善,且纸浆不易返黄;纸页的抗张指数、耐破指数、撕裂指数均有不同程度的改善;添加天然介体的P段废水CODCr值明显低于合成介体HBT的废水CODCr值,且低于未添加介体的空白试验废水CODCr值。因此,天然介体比合成介体在改善纸浆性能、降低漂白废水污染方面更具优势。 相似文献
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漆酶和漆酶/介体处理提高未漂化学木浆湿强度的研究 总被引:8,自引:0,他引:8
研究了漆酶和漆酶/介体体系处理对未漂硫酸盐浆强度和白度的影响。结果表明,与空白样相比,漆酶处理可显著改善纸浆的湿抗张强度,但对干抗张强度和撕裂强度无明显影响,且纸浆白度有所降低。丁香酸甲酯(MS)是一种高效的介体,介体本身对纸张的强度和白度无影响,但与漆酶协同作用可使纸浆的湿抗张强度提高1倍以上。漆酶最佳用量为16U/g绝干浆;丁香酸甲酯的最佳用量为0.5%。高温干燥有助于提高纸张的再湿强度,在单独使用漆酶处理时更为重要。在单独漆酶处理过程中,通氧与通空气对提高湿抗张强度的效果无明显区别;而漆酶/介体体系处理中,通氧气可获得比通空气更高的湿强度指标。 相似文献
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利用NS51003漆酶对三倍体毛白杨APMP纸浆进行生物酶处理,并对处理后纸浆的化学、物理性能进行测定。研究结果表明:利用漆酶NS51003处理三倍体毛白杨APMP一段纸浆,可有效提高一段纸浆的白度及物理强度;而且漆酶处理后的三倍体毛白杨APMP纸浆中残余木素含量与未经处理的纸浆相比有所降低;利用漆酶NS51003处理三倍体毛白杨APMP二段纸浆,可有效提高纸浆强度性能。 相似文献
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利用NS51003漆酶处理三倍体毛白杨碱性过氧化氢机械浆(APMP),通过分析检测处理后纸浆的打浆度和成纸物理性能探讨了漆酶处理对三倍体毛白杨APMP抄造性能的影响。实验结果表明,在最佳的工艺条件下,漆酶处理APMP与未经过漆酶处理纸浆相比,抗张指数和耐破指数稍有升高,而撕裂指数提高了16mN·m2/g,酸溶木质素含量稍有升高,Klason木质素含量相对降低;漆酶处理三倍体毛白杨APMP主要降解纸浆中纤维表面的木素,对纤维内部影响较小。 相似文献
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该文采用漆酶处理漂白ONP脱墨浆,研究了漆酶处理方式对成纸白度和强度性能的影响,并通过XRD和AFM观察了纤维结晶度和表面形貌的变化。结果表明:漆酶处理可以提高成纸白度3.70%ISO,提升成纸的撕裂指数9.02%、抗张指数18.40%和耐破指数2.79%,纤维结晶度由75.9%降至72.5%。另外,从AFM的图像可以看出漆酶处理后的纤维表面变得粗糙。粗糙的纤维比表面积大,易使纤维结合紧密,从而使得成纸强度上升。 相似文献
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