漆酶在造纸工业中应用的最新研究

漆酶是近年发现在造纸工业中最具潜力的生物酶,具有催化氧化木素的能力。文章综述了漆酶在制浆造纸工业中应用的最新研究进展,例如漂白、造纸废水处理、去除树脂、增加湿强度等诸多方面。     

高活性漆酶产生菌的发酵条件优化

对云芝菌产漆酶的发酵条件进行优化,考察C源、N源和诱导剂等因素对产酶的影响.结果表明:杂色云芝菌摇瓶产漆酶的最佳条件为葡萄糖1.25 g/L,羧甲基纤维素钠15 g/L,酵母膏15 g/L,KH2PO41 g/L,CaCl20.05 g/L,MgSO40.25 g/L,30℃、150 r/m条件下振荡培养,在72 h加入2 mmol/L 2,5-二甲基苯胺作为诱导剂,在96 h加入2 mmol/L Cu2+,经过7 d培养,菌的漆酶比活达到3 319.2 U/mL.     

Effect of HBT on the stability of laccase during the decolourization of textile wastewaters

BACKGROUND: This study concerns the assessment of laccase stability during textile industry effluent treatment by laccase in the presence of a mediator RESULTS: The effects of 1‐hydroxybenzotriazole (HBT) and textile wastewater on the stability of a crude laccase prepared from cultures of Trametes trogii during the process of textile industry effluent decolourization were determined. HBT was essential for decolourization of effluent by laccase. Decolourization efficiency decreased when effluent was repeatedly added to the reaction mixture, suggesting inhibition of laccase during the process. Stability of the laccase was not affected by different concentrations of effluent, but inactivation was proportional to HBT concentration. CONCLUSION: Experimental results showed that a redox mediator such as HBT was required for high decolourization rate of textile industry effluent; however free radicals generated from this compound inactivated the laccase used in the process. Copyright © 2009 Society of Chemical Industry     

Hydrogen peroxide concentration measured in cultivation substrates during growth and fruiting of the mushrooms Agaricus bisporus and Pleurotus spp.

Hydrogen peroxide is suspected of being highly implicated in mushroom nutrition and in substrate bleaching during cultivation. The parameters for measuring H₂O₂ in compost samples were examined and the methodology was applied to samples from both compost colonized by cultivars and wild isolates of Agaricus bisporus, and wheat straw or coffee pulp colonized by Pleurotus spp. Laccase and peroxidase activities were also measured. H₂O₂ concentration measured after heating at 80 °C for inactivating laccases and peroxidases was probably both H₂O₂ pre‐existing in the compost and H₂O₂ generated from quinones and active oxygen species. This potential H₂O₂ concentration increased during the vegetative growth for all the strains, in agreement with a direct relationship between H₂O₂ concentration and active biomass of A. bisporus or Pleurotus spp. in their cultivation substrates. Correlations were observed between H₂O₂ concentration and manganese peroxidase activity in cultivation substrates at the stage of primordia formation. At this stage of development, H₂O₂ generation via biotic or abiotic mechanisms should be an important physiological trait of mushrooms. Copyright © 2007 Society of Chemical Industry     

Cu~(2+)修饰低固载量固定化漆酶的活性研究

由于漆酶这种生物蛋白酶有容易变性失活且不可重复使用的特性,限制了漆酶的应用和发展。因此如何提高漆酶的活性,稳定性以及重复使用性尤为重要。本文采用交叉偶联技术,将漆酶固定在具有核壳结构的磁性纳米粒子Fe3O4/SiO2上,并研究了用Cu2+修饰后的低固载量固定化漆酶的活性变化以及修饰后固定化漆酶的稳定性。实验结果显示:Cu2+修饰后的低固载量固定化漆酶的相对活性提高了54%;而且在温度不太高的情况下,修饰后的低固载量固定化漆酶的相对活性优于修饰前的固定化漆酶;修饰后的固定化漆酶降解浓度为10mg·L-1的普施安染料,重复利用13次后降解率仍然可以达到92%。     

Investigating the Role of Conformational Effects on Laccase Stability and Hyperactivation under Stress Conditions

Fungal laccase from Steccherinum ochraceum 1833 displays remarkable stability under different harsh conditions: organic/buffer mixtures, thermal treatment, and microwave radiation. The behavior is particularly significant in the light of the sharp inactivation observed for two different fungal laccases. Laccase from S. ochraceum 1833 also displays hyperactivation under mild thermal treatment (60 °C). Molecular dynamics simulations at 80 °C explained how this laccase retains the geometry of the electron transfer pathway, thereby assuring electron transfer through the copper ions and thus maintaining its catalytic activity at high temperature. Spectroscopic studies revealed that the thermal activation corresponds to specific conformational changes in the protein. The results indicate that this laccase is potentially applicable under denaturing conditions that might be beneficial for the biotransformation of recalcitrant substrates.     

A comparative study of water dispersible polyaniline nanocomposites prepared by laccase‐catalyzed and chemical methods

A comparative study of chemical and enzymatic methods of aniline polymerization was carried out. Fungal laccase from Trametes hirsuta was used in the synthesis of polyaniline nanoparticles made with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPS). Template polymerization of aniline was carried out in aqueous buffer. It was shown that the laccase had high long‐term and operating stabilities under acidic condition favorable for synthesis of conducting polyaniline. UV‐vis, FTIR spectroscopy, and cyclic voltammetry analysis are used for the characterization of the polyelectrolyte complexes of polyaniline and PAMPS. The incorporation of the polymeric acid in polyaniline has been demonstrated by atomic force microscopy. The size and morphology of the nanoparticles of the polyaniline–PAMPS complexes depended on the method of the synthesis. A comparison of some physical and chemical properties of water dispersible conducting polyaniline–PAMPS was performed under production by enzymatic and chemical methods. It was found a difference in structures and some physicochemical properties of polyaniline colloids prepared by chemical and laccase‐catalyzed methods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010