Laccase improvement in submerged cultivation: induced production and kinetic modelling

Improvement of laccase production by Trametes versicolor was made by employing different operational strategies. In the cell growth medium, various glucose concentrations were compared for improving laccase production. A clear and significant stimulation of enzyme production under carbon limitation was obtained. Copper, 2,5‐xylidine, and a phenolic mixture were also used as laccase inducers. A cooperative effect between the inducers on laccase production was identified. Mixtures of inducers produced higher laccase activities, reaching values of 5500 U dm^?3. Further productivity enhancement can be obtained using the inducers along with the carbon limitation strategy. It is shown that low laccase concentrations are obtained by a primary metabolism of T versicolor, and that phenolic compounds and carbon limitation induce a secondary metabolism, providing higher laccase concentrations. A mathematical model for laccase production based on a direct experimental measure of biomass, along with substrate consumption and enzymatic activity over time is proposed for non‐homogeneous fermentations of T versicolor. Copyright © 2005 Society of Chemical Industry     

液体发酵生产云芝糖肽

通过5株云芝菌种筛选，获液体发酵生产云芝糖肽较好的菌株Y—1和Y-4，摇瓶作为一级种子放大至50L全自动罐发酵，28℃、4d，菌丝体干重达24．8g／L。将菌丝体破碎、超滤浓缩、醇沉干燥后，云芝胞内糖肽产率达2．21g／L，糖肽总糖为54．7％，肽32．95％。     

漆酶产生菌的原生质体诱变选育

利用紫外线对杂色云芝原生质体进行诱变,经原生质体再生培养和筛选再生菌株,获得一株高产漆酶突变株,突变株比出发菌株的漆酶酶活提高了54.32%.而且,突变株继代遗传稳定,说明利用原生质体紫外诱变育种是获得漆酶高产菌的一种有效方法.     

利用木质素沉淀物产漆酶的研究

从玉米秸秆的碱处理液中分离木质素沉淀物,进一步用于Coriolus versicolor液态发酵生产漆酶。研究结果表明,木质素沉淀物对漆酶的形成有明显的促进作用,当其添加量为0.6%时,在摇瓶条件下漆酶活力可高达7005.6IU/ml,比对照组的漆酶活力提高了4.04倍。发酵培养基中添加10g/L葡萄糖有利于菌种的前期生长,从而提高漆酶产量。在3.7L发酵罐中进行产酶试验,发酵罐最适通气量为0.75vvm,最适转速为300r/ min,漆酶活力可达到7506.2IU/mL。该试验结果对于降低玉米秸秆碱预处理液的环境污染,促进木质素沉淀物的回收利用以及加速漆酶的规模化生产等均具有重要意义。     

Laccase‐catalysed oxidation of aqueous triclosan

A study was conducted on the ability of laccase from Trametes versicolor to catalyse the oxidation of triclosan, an antibacterial agent of significant commercial importance and environmental concern. Laccase was able to catalyse the transformation of triclosan under a variety of conditions and achieve a substantial decrease in toxicity of the reaction mixture. The optimal pH for triclosan transformation was approximately 5, with a broad optimum in the range 4–6. Treatment could be achieved at elevated temperatures, but at the expense of higher rates of inactivation. Treatment efficiency and reaction rates were substantially improved through the use of a protective additive, poly(ethylene glycol) (PEG‐35 000), and a mediator, 2,2′‐azino‐bis(3‐ethylbenzthiazoline)‐6‐sulfonic acid (ABTS). However, both compounds negatively affected the toxicities of treated solutions. The presence of ions including sulfite, sulfide, cyanide, chloride, iron(III) and copper(II) resulted in reduced treatment efficiency. Copyright © 2006 Society of Chemical Industry     

关于微生物溶煤作用几个影响因素的研究

利用云芝（ｐｏｌｙｐｏｒｏｕｓｖｅｒｓｉｃｏｌｏｒ）和假丝酵母（ｃａｎｄｉｄａＭＬ－１３）进行扎赍诺尔褐煤和平在褐煤溶解试验。结果表明：改变培养基组成、接种量等菌种培养条件和溶煤温度、溶煤作用时间及体系氧入量、溶煤方式等溶煤条件均影响溶煤效果。     

发酵产云芝胞外多糖的分析及其在卷烟中的应用

对发酵产云芝胞外多糖进行提取和脱蛋白处理得到精制云芝胞外多糖,之后过SepharoseCL-6B凝胶柱得到一个多糖组分,然后用红外光谱技术对该多糖组分的结构进行表征得知其为酸性多糖;将精制云芝胞外多糖以不同的浓度注入卷烟中,利用吸烟机捕集烟气粒相物计算出云芝胞外多糖在烟气中的转移率在2.76%～4.78%之间变动;用单料烟丝进行加香评吸实验,结果表明在精制胞外多糖添加量为0.04%时明显地改善了卷烟的吸食品质,起到掩盖杂气,去除刺激,改善余味的作用,使香气细腻程度有所提升。这为发酵产云芝胞外多糖在卷烟中的应用提供了一定的理论支持。     

Effects of Onion (Allium cepa L.) and Garlic (Allium sativum L.) Essential Oils on the Aspergillus versicolor Growth and Sterigmatocystin Production

Abstract: In the present study the effects of individual and combined essential oils (EOs) extracted from onion (Allium
cepa L.) bulb and garlic (Allium sativum L.) clove on the growth of Aspergillus versicolor and sterigmatocystin (STC) production were investigated. The EOs obtained by hydrodistillation were analyzed by GC/MS. Twenty one compounds were identified in onion EO. The major components were: dimethyl‐trisulfide (16.64%), methyl‐propyl‐trisulfide (14.21%), dietil‐1,2,4‐tritiolan (3R,5S‐, 3S,5S‐ and 3R,5R‐ isomers) (13.71%), methyl‐(1‐propenyl)‐disulfide (13.14%), and methyl‐(1‐propenyl)‐trisulfide (13.02%). The major components of garlic EO were diallyl‐trisulfide (33.55%), and diallyl‐disulfide (28.05%). The mycelial growth and the STC production were recorded after 7, 14, and 21 d of the A. versicolor growth in Yeast extract sucrose (YES) broth containing different EOs concentrations. Compared to the garlic EO, the onion EO showed a stronger inhibitory effect on the A. versicolor mycelial growth and STC production. After a 21‐d incubation of fungi 0.05 and 0.11 μg/mL of onion EO and 0.11 μg/mL of garlic EO completely inhibited the A. versicolor mycelial growth and mycotoxins biosynthesis. The combination of EOs of onion (75%) and garlic (25%) had a synergistic effect on growth inhibition of A. versicolor and STC production. Practical Application: A substitution of synthetic preservatives with natural antimicrobial compounds in food safety to control fungal contamination and mycotoxin production.     

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid and its derivatives using enzyme from white-rot fungus Trametes versicolor: Enzyme characteristics and its application

Transformation of 3,5-dimethoxy-4-hydroxy cinnamic acid (sinapic acid), sinapaldehyde, sinapine and sinapoyl in the model system containing an enzyme secreted by the fungus Trametes versicolor was investigated. The affinity of this enzyme was highest for sinapic acid followed by sinapaldehyde and sinapine. The optimum temperature and pH for these transformations were 50°C and pH 3·3, 50°C and pH 4·5, 60°C and pH 4·0 for sinapaldehyde, sinapine, and sinapic acid, respectively. The apparent heat of the enzyme-sinapic acid complex formation is −2557·6 J mol⁻¹. Higher concentrations of sinapine and sinapic acid caused enzyme inhibition. When canola meal was treated with this enzyme the phenolics content in this commodity was decreased by 90%.     

不同云芝菌株腐朽杨木过程的扫描电镜研究

本文应用扫描电镜观察研究了白腐菌云艺（Coriolusvericolor）三个菌株腐朽杨木的过程，对试材的显微形态变化以及各菌株的降解特性进行了详细描述和探讨．实验结果表明，三个菌株降解木材的性能和方式存在着差异。NFU008对木质素和纤维素均具有很强的降解能力，它在腐朽早期优先降解胞间层中的木质素并能使纤维解离，在腐朽后期，它对纤维素产生强烈降解。NFU006对木质素和纤维素的降解是同时进行的，但对纤维次生壁中木质素的降解率明显高于对纤维素的降解率。NFU019降解木质素的能力相对较弱，但对纤维素的降解能力却很强，早期它以降解出生壁的木质素为主，而在腐朽后期它对纤维素产生剧烈降解。三个菌株最终均造成纤维细胞壁不同程度的减薄和破坏。