白腐菌对活性艳红的降解研究

白腐真菌是一类丝状真菌,由于能分泌漆酶(Lac),锰过氧化物酶(Mn P)和木质素过氧化物酶(Lip)在废水处理方面有着广泛的应用。本实验初步探究了白腐菌对不同浓度活性艳红的脱色效果,实验结果表明活性艳红浓度在10-60 mg/L的浓度下并没有引起白腐菌毒性,并且白腐菌对活性染红的脱色主要有菌丝体的吸附和酶的降解两方面的作用。     

碳源对平菇选择性降解稻草木素及其后续酶解性能的影响

前期研究发现,平菇预处理稻草表现出比较好的脱木素选择性和纤维素酶水解效果。为了使预处理后的稻草在纤维素酶水解过程中得到更多的单糖,通过向平菇预处理稻草固体培养基中添加麸皮、玉米皮和木聚糖,研究外加碳源对平菇降解稻草木素的选择性及后续酶水解效果的影响。结果表明,添加适量的麸皮和木聚糖可提高平菇处理稻草的脱木素选择性。麸皮和木聚糖添加量为稻草粉的10%时,脱木素选择系数分别由对照的1.86增加至2.58和2.03;预处理样品酶解后原料中总糖的46.8%和45.9%转化为可发酵单糖,分别比对照的35.5%提高了30%和28%。添加玉米皮对平菇预处理酶解效果影响相对较小,添加量为5%时,预处理样品酶解后总糖转化率仅比对照提高15%,增加添加量酶解总糖转化率反而低于对照样品。     

三种白腐菌对木质纤维素降解规律的初步研究

以接种量1%、接种龄7天为基准,在天然培养基及室温条件下,探讨了三种白腐菌对稻草秸秆中木质纤维素的降解动力学特性。结果表明,对木质素的降解速率桦褐孔(Inonotus sp)最高,红平菇(Pleurotus djamor)次之,白韧(Trametes sp)最低;对纤维素的降解速率与此正好相反。三菌株对木质纤维素的降解呈现一定的选择性,其中桦褐孔(Inonotus sp)对木质素的选择性降解优势最明显,选择系数达到2.99。     

白腐菌降解木质素酶系的特征及其应用

介绍了木质素降解白腐菌的菌属来源及其酶系特征,重点解析木质素过氧化物酶、锰过氧化物酶和漆酶3种酶的催化作用机理;归纳了不同种属白腐菌在生物制浆过程、生物漂白过程及在造纸、印染等产业废水处理过程中的研究应用成果,针对白腐菌应用上的问题提出了未来的研究重点和方向。     

一株木质素降解细菌的筛选及其降解途径

经高温碱性盐法预处理的玉米秸秆预处理液中木质素和碱性盐含量高,为了反复利用含盐预处理液,需脱除其中的可溶性木质素。本实验从腐木中筛选分离到一株木质素降解菌株CCZU-WJ6,通过形态学观察和16S rDNA序列分析,鉴定该菌株属于无色杆菌属（Achromobacter sp.）。测定了CCZU-WJ6木质素降解相关酶的活性,及其在玉米秸秆预处理液中的生长趋势、预处理液的COD去除率和木质素降解率,通过GC-MS和FTIR检测预处理液中组分及其化学键的变化。通过单因素实验确定了菌株CCZU-WJ6处理预处理液的最佳条件为pH 7.0、温度30℃、预处理液稀释倍数10倍、接菌量0.5g/mL。在处理6天后,预处理液COD脱除率为40.9%,木质素的降解率为32.1%,CCZU-WJ6分泌木质素过氧化物酶和锰过氧化物酶的酶活分别达到215.5U/L、200.1U/L。CCZU-WJ6会破坏木质素结构中的苯环结构、醚键以及C＝O键,降解产物中含有愈创木酚和对香豆酸,推断其降解途径为β-芳基醚代谢途径和阿魏酸代谢途径。CCZU-WJ6可用来处理含木质素的工业废水,在工业方面具有广阔的应用前景。     

醋酸预水解对稻草化学成分及酶水解性能的影响

研究了醋酸预处理对稻草主要化学成分及酶水解糖化效率的影响。在160℃下以不同的醋酸用量(0～4%)对稻草进行处理,预处理后稻草的Klason木质素含量基本保持不变,约60%的酸溶木质素被脱除;灰分含量(质量分数)约下降30%,灰分中SiO2则几乎全部保留在预处理浆料中。预处理醋酸用量的增加对酸溶木质素和灰分含量的变化均无显著影响。预处理后高聚糖的降解程度随醋酸用量的增加而上升,其中半纤维素的降解程度尤为显著,阿拉伯聚糖、半乳聚糖大量溶出。对经醋酸预处理稻草的酶水解研究表明,预处理中醋酸用量的增加无助于酶水解液中还原糖得率的提高。稻草于160℃下经不添加醋酸的自水解预处理后,其酶解还原糖得率均高于经醋酸预处理的稻草,当纤维素酶用量为40 FPU/g(对底物)时,稻草中高聚糖的酶水解转化效率最高,葡聚糖、木聚糖的转化率分别为67.8%和45.3%,总糖转化率为58.8%。     

一株用于印染废水脱色菌产漆酶条件的优化

脱色菌—白腐真菌主要用于纤维素、木质素的降解,在稻草降解、产酶量等方面报导较多,但对于用脱色菌-白腐真菌用于印染废水脱色菌种培养基优化报导较少。文章从白腐真菌产漆酶条件入手,试求对其产漆酶条件进行优化。     

不同体系下白腐菌对染料的脱色研究

研究了土豆液体、稻草液体和稻草固体3种培养体系下白腐菌脱色染料的特性。结果表明,含稻草秸秆的培养体系均能较好促进菌株生长、木质素酶系分泌和染料脱色。稻草液体培养体系下生物量在第12天高达3.1g/L;稻草固体培养体系下白腐菌主要分泌漆酶,其次还有锰过氧化物酶和木素过氧化物酶,其中漆酶活力在第5天高达428U/mL,是稻草液体培养体系中漆酶活力的2.9倍;稻草液体和固体培养体系下,菌株分别在第8天和第5天对染料脱色高达90.85%和92.78%,远超过土豆液体培养体系。     

白腐菌木素过氧化物酶发酵条件及其酶液对稻草降解的研究

研究营养条件对白腐菌合成木素过氧化物酶(ligninperoxidase,LiP)的影响。在最适培养条件下,第6天获得7560U/L的酶活。利用LiP粗酶液在体外直接降解稻草,3天后Klason木素的降解率为8.7%,经红外光谱分析其降解产物,推断LiP粗酶液在体外降解稻草的反应主要是氧化反应。     

选择性降解木质素白腐菌筛选的研究

对国内外15种产漆酶的白腐菌进行初步筛选,从中获得7株产漆酶活性较高的菌株。经对木材降解能力的分析及在培养过程中所产各种酶酶活的测定,得到了2株产漆酶酶活高、降解木质素选择性优良的菌株,其中Flammulinavelutipes和My-1两菌株经14天液体培养,漆酶酶活高达214IU/mL和231IU/mL。杨木经其处理30天后木质素降解率达到22.67%和15.46%。     

云芝、脉射菌产木质素降解酶的比较研究

对两种白腐菌——云芝(Coriolus versicolor)和脉射菌(Phlebia radiata)在静置液体培养条件下最适产漆酶和赖锰过氧化物酶(MnP)的培养液组成进行了比较研究,同时,还对此二菌在产酶过程中还原糖的消耗与蛋白质积累变化进行了检测分析。     

固定化白腐菌处理苇浆氯漂碱抽提段废水的研究──不同因素对脱色效果的影响

比较了几株不同白腐菌经固定化后处理E段氯漂废水的脱色效果。发现白腐菌Polystictusversicolor和Phlebiaradiata的脱色效果最好,废水色度在24h内可有效降低达50％。在处理废水过程中,不同的白腐菌对介质pH值的适应性有所不同。附加碳原和氛语的添加与否,对固定化白腐菌处理废水的脱色效果影响不大。     

Synergistic effect of pretreatment and hydrolysis enzymes on the production of fermentable sugars from date palm lignocellulosic waste

The sequential addition of the enzymes, laccase for lignin degrading, followed by xylanase for hemicelluloses hydrolysis, then cellulase for cellulose hydrolysis, was compared to the synergistic action of using the three enzymes together. It was shown that the reducing sugars yield increased from 5.6% using cellulase only to 45.6% by pretreatment with laccase and xylanase, prior to the enzymatic hydrolysis. A higher conversion of 60% was achieved by using the three enzymes together for the same incubation period. The proposed synergistic enzymes approach is a simpler and less energy intensive alternative compared to the conventional lignocelluloses pretreatment techniques.     

Enzymatic saccharification of dissolution pretreated waste cellulosic fabrics for bacterial cellulose production by Gluconacetobacter xylinus

BACKGROUND: Waste textiles, such as dyed cellulosic and/or polyester blended fabrics have the potential to serve as an alternative feedstock for the production of biological products via microbial fermentation. Dissolution pretreatment was employed to enhance the enzymatic saccharification of dyed and synthetic fiber blended cellulosic fabrics. The fermentable reducing sugars obtained from waste cellulosic fabrics were used to culture Gluconobacter xylinus for value‐added bacterial cellulose (BC) production. RESULTS: Concentrated phosphoric acid was the ultimate cellulose solvent for dissolution pretreatment since 5% w/w cellulosic fabric can be completed dissolved at 50 °C. After regeneration in water, the cellulosic precipitate was subjected to cellulase hydrolysis, resulting in at least 4‐fold enhancement of saccharification rate and reducing sugars yield. The colored saccharification products can be utilized by G. xylinus to produce BC, approximately 1.8 g L^?1 BC pellicle was obtained after 7 days static cultivation. CONCLUSION: Dyed and blended waste fabric can be pretreated effectively by dissolution to produce fermentable sugars by cellulase hydrolysis. Dissolution pretreatment can expose the dyed or polyester fiber covered digestible cellulosic fibers to cellulase and leads to a significant enhancement of saccharification yield. The colored saccharification products have no significant inhibiting effect on the fermentation activity of G. xylinus for BC production. Copyright © 2010 Society of Chemical Industry     

Xylanase-Resistant Xylan In Unbleached Kraft Pulp

A water-soluble chromophoric xylanase-resitant xylan fraction (LF-D) was separated from a hardwood unbleached kraft pulp (UKP) after hydrolysis with a cellulase/ xylanase-membrane bioreactor. LF-D contained over 70% unremovable inorganic atoms including Si, Na, and S, together with a β-1,4- linked xylan. A nucleus exchange reaction and a nitrobenzene oxidation showed that LF-D contained a trace amount of a lignin component abundant in quinoid structures which had been partly demethylated during the course of kraft pulping. On the other hand, a higher molecular weight residual lignin fraction (HF-P), which was obtained from an impermeable part of the enzymatic digests, was found to have a diphenylmethane structure. LF-D was partially decolorized by Coriolus versicolor and bacterial microflora without action of extracellular lignin peroxidase, Mn-peroxidase, laccase or xylanase.     

染料废水白腐真菌生物降解新方法探寻

染料废水的脱色处理一直是环境污染防治中一个棘手的难题。目前,已有大量关于白腐真菌降解染料废水的研究。本文综合前人的研究结果,重点分析目前研究较多的浸没式白腐真菌生化反应器所存在的问题。并在此基础上,提出“秸秆吸附一白腐真菌固体发酵”复合工艺降解染料废水,以期能为治理染料废水的研究提供新的方向。     

The Wood Preservative Potentials of Valonia,Chestnut, Tara and Sulphited Oak Tannins

This study investigated antifungal properties of four different tannins as potential environmentally friendly wood preservatives. Scots pine wood samples were impregnated with 3, 5, 10, and 15% valonia, chestnut, tara, and sulphited oak tannins, and then were exposed to brown rot fungi Coniophora puteana and Postia placenta, and white rot fungi Trametes versicolor and Pleurotus ostreatus attack to determine the best tannin type and the optimum concentration level for sufficient decay resistance. Leaching test was conducted in order to evaluate any loss in effectiveness in decay resistance due to possibility of tannin leaching. Tannins were found efficacious in suppressing brown rot fungi attacks when no leaching prior the decay test was used, however, they seemed to be ineffective against white rot fungi attacks. The lowest weight losses were obtained with valonia and chestnut tannins both for brown and white rot fungi probable related with their high ellagic tannin content.     

固定化白腐菌处理氯漂碱抽提段废水的研究──驯化预处理的影响

将白腐菌在进行驯化预处理并固定化后，处理苇浆氯漂碱抽提段废水，发现驯化预处理能明显提高固定化白腐菌的脱色能力。将一次驯化，二次驯化和球体驯化的效果进行比较发现，一次驯化可达到较佳处理效果。固定化驯化Polystictusversicolor和Phlebiaradiata可在24小时内使废液脱色50％。