白腐菌降解木质纤维素顺序规律的研究

通过纤维素、半纤维素和木质素三者含量变化的测定,以及傅立叶变换红外光谱(FTIR)的谱图分析,研究了 BP2、CD1和 AX3三株白腐菌在50 天培养期中降解木屑基质中木质纤维素的规律。结果表明,三株白腐菌对木屑基质中纤维素、半纤维素和木质素三者的降解具有一定的顺序和选择性,即先降解半纤维素和木质素,再同时降解半纤维素、纤维素和木质素;从降解比例来看,三株菌对木质素具有很强的降解优势(45%左右)和选择性(0.5左右)。木质素的相关谱带(1630,1510,1325 和 1265 cm-1)强度及半纤维素和纤维素的相关谱带强度(1740,1325,1160 和 898 cm-1)的变化也证实了这一结论。     

木质纤维素微生物转化机理研究进展

木质纤维素是自然界中储量最大的可再生资源物质,由于木质素难以降解,阻碍了木质纤维素物质的生物转化利用,并且是相关工业生产中毒性污染物质的主要来源。自然界中存在的白腐真菌对芳香族化合物具有很强的降解能力,具有完整的木质纤维素降解体系,对这一体系的研究成为实现木质纤维素资源转化利用的关键,木腐微生物的存在,使人类通过廉价手段降解和利用木质纤维素成为可能。研究木腐微生物降解木质纤维素的机制,研究木质素降解酶类不同组分以及和小分子活性物质之间协同作用机理,筛选培育高效降解木质纤维素的菌种和木质素降解酶,为实现工业化转化利用木质纤维素奠定基础。     

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。     

固态发酵中纤维素基质降解过程初步研究

利用斜卧青霉(Penicillium decumbens JUA10)对汽爆麦草和淀粉质的混合基质进行固态发酵，通过分析各种成份及酶活力变化，研究了各成份的降解速率，并探讨了纤维素、半纤维素降解与纤维素酶、半纤维素酶酶活力的关系. 纤维素基质固态发酵中木质纤维素的降解过程实际是同步糖化发酵过程，还原糖不会积累形成对纤维素酶、半纤维素酶的反馈抑制；纤维素降解与纤维素酶的酶活性、半纤维素的降解与半纤维素的酶活性不成正比. 木质纤维素的降解难主要是木质纤维素结构造成的. 半纤维素的降解甚至比纤维素降解更慢，淀粉容易降解，木质素几乎不降解.     

固定化白腐菌对造纸废水的生物降解研究

就具有较强木质素降解能力的白腐菌对造纸废水的降解效果及条件进行了初步研究.分别采用固定化白腐菌和悬浮态白腐菌在不同接种量下对造纸废水进行降解,对降解过程中的白腐菌生长量、pH、COD、木质素含量等废水降解指标进行测定.结果显示两种不同状态下的白腐菌均能降解造纸废水,但它们的降解程度不同.其中固定化白腐菌降解木质素效果较好,且呈现较明显规律,说明固定化的白腐菌较悬浮态的白腐菌更具有降解造纸废水的潜在能力.     

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。     

麦草自水解过程中半纤维素和木质素的变化特性

自水解对木质纤维生物质转化利用具有重要意义,研究了自水解对麦草化学成分变化的特性。结果表明:温度和时间对麦草自水解化学成分变化有重要影响,温度170℃时,半纤维素与木质素的降解均呈现两个阶段,即保温60 min前的快速脱除阶段和60 min后的慢速脱除阶段,半纤维素脱除率分别为65.0%和16.7%,Klason木质素脱除率分别为33.0%和2.7%,酸溶木质素脱除率分别为66.1%和11.7%;自水解大大提高麦草苯醇抽出物含量,170℃保温210 min后苯醇抽出物含量达15.9%。麦草自水解具有生物炼制特点。     

玉米秸秆木质素降解过程的CP/MAS 13CNMR和SEM表征

利用黄孢原毛平革菌对玉米秸秆木质素进行降解处理,通过CP/MAS 13 CNMR和SEM研究降解过程中木质素的结构变化。CP/MAS 13 CNMR结果表明:玉米秸秆木质素降解过程中,作为木质素结构单元主要连接方式的β-O-4键基本上没有被降解;木质素单位苯环的甲氧基含量稍有增加;S/G值降低,推断反应过程中紫丁香基优先参与反应。SEM结果表明:降解后的木质素空穴增多且增大、颗粒物质减少,主要是由于酶解木质素中大量碳水化合物的降解所致;比木质素更容易降解的纤维素和半纤维素也存在于样品中。CP/MAS 13 CNMR为木质纤维原料结构的定性和初步定量提供了可能,是传统定量表征手段的有力补充,具有一定的研究意义。     

不同化学处理方法对水稻秸秆结构的影响

对稻秆进行化学预处理是提高其生物降解效率的重要手段。为明确不同化学处理方法对稻秆结构特性的影响,论文分别用碱和液氨对水稻秸秆进行处理,研究不同化学处理方法对水稻秸秆物化性质、结构形貌、纤维成分及微孔结构的影响,并考察其生物降解性能。结果表明:碱化处理和氨化处理都能打破稻秆纤维素、半纤维素和木质素间的氢键,明显改变稻秆的物化性能,增加微孔结构,降低木质素含量,增加半纤维素含量,但碱化处理对稻秆表面结构的破坏程度要高于氨化处理;碱化处理稻秆表现出更好的生物可降解性,在50℃时用复合菌系XP降解Na OH处理稻秆7d,其失重率和纤维素、半纤维素、木质素的降解率分别达到73.6%、77%、93%和31%,显示了碱化稻秆良好的生物可降解性。     

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。     

玉米秸秆氨化汽爆处理及其固态发酵

在加氨条件下对玉米秸秆进行了汽爆处理(简称氨化汽爆)和固态发酵. 结果表明: 氨化汽爆同样可使秸秆中的半纤维素降解,并使玉米秸秆的酶解率提高到42.97%, 同时可使秸秆的有机氮含量提高1.27倍. 利用氨化汽爆秸秆进行固态发酵,可提高蛋白含量到23.45%,比不加氨汽爆的玉米秸秆提高了1倍. 而加过氧化氢的氨化汽爆不利于微生物发酵.     

小麦秸秆水热预处理半纤维素降解动力学研究

水热预处理是木质纤维素原料高效能源转化的主要工艺流程之一,但是以小麦秸秆为原料的水热预处理的反应路径与反应机理仍有研究不足之处, 制约该预处理过程的优化及实际生产应用。本文以小麦秸秆为研究对象,实验研究了木质纤维素水热预处理过程反应动力学。研究发现,在水热预处理过程中,小麦秸秆的主要降解过程是半纤维素降解产生低聚木糖、木糖以及糠醛的过程,半纤维素在水热过程中几乎完全降解。随着预处理温度的升高,水解液中低聚木糖和木糖的浓度降低,而糠醛的浓度增加;随着保温时间的延长,低聚木糖与木糖的浓度先增加后减小,糠醛的浓度会趋于稳定。根据实验结果提出反应路径并拟合获得动力学速率常数和反应活化能,所获的动力学模型可以很好地解释反应物浓度的变化,与实验数据吻合良好。该模型可以为小麦秸秆水解预处理系统的设计提供参考。     

Biogenic Catalysis by Adding Compost when Using Wheat Straw in a Biorefinery Concept

The high content of lignocellulose limits the biodegradability of wheat straw for bioenergy production. To counteract this fact, a thermobiological pretreatment was applied to improve the utilization of lignocellulose biomasses for a biorefinery concept. The use of compost assured the growth of cellulose-degrading anaerobic microorganisms under thermophilic conditions. Results revealed a lignocellulose material degradation in all samples. Moreover, the combination of a thermobiological pretreatment under thermophilic conditions created a synergistic effect that accelerated the biomethanization of wheat straw due to the sugar compounds released during the biogenic catalysis.     

白腐真菌对活性艳红X-3B脱色性能的试验

初步探讨了白腐真菌对偶氮染料活性艳红X-3B废水的脱色效果。试验过程在一种特制的白腐真菌生物反应器中进行。试验结果表明培养液的类型、碳源物质的浓度和温度对白腐真菌的脱色能力有重要的影响。培养液类型对染料的脱色效果有显著的影响,试验所用的第一种共培养液不但有利于脱色,而且具有很好的缓冲能力。低浓度碳源试验条件有利于增强和加速对活性艳红X-3B染料的脱色过程。白腐真菌是嗜热真菌,温度较高有利于脱色反应的进行。     

Degradation of rice straw by Pleurotus flabellatus

Degradative changes in the constituents of rice straw substrate during the growth and commercial production of fruit bodies by Pleurotus flabellatus were investigated. There was a continuous increase in the free sugars from the time of inoculation until the end of harvesting of the fruit bodies, whereas the free amino acids reached a maximum at the end of mycelial growth and showed a slight decrease after fructification. Glucose, xylose, arabinose, cellobiose and a higher oligosaccharide represented the spectrum of sugars produced. Of the 12 amino acids (apart from two peptides) identified, aspartic acid, histidine and tyrosine were the major components. Solubilities and spectral characteristics of lignin degraded in the straw substrate were studied using alkali-extracted lignin. Laccase and protease activities in the straw substrate at different stages of fungal degradation could be correlated to the decreases in the staw lignin and protein contents, respectively. Colour reactions of the fungus on several phenolic media, demonstration of phenolic oxidases in the straw substrate, and ability of the fungus to degrade lignin conclusively proved that the fungus under study is a typical ‘white rot’ fungus. Degradation of the straw substrate by the fungus reached a maximum at the end of harvest of the fruit bodies. The spent straw substrate (left over after harvesting the fruit bodies) contained free sugars and amino acids, respectively 5 and 2 times the concentration of those in the undegraded straw substrate, and lignin decreased to about 25% of the level in the straw before fermentation. Potential applications of the spent straw substrate as an upgraded form of rumen feed and for the production of single-cell protein are discussed.     

白腐菌降解焦化废水的研究

介绍了白腐菌在焦化废水中的驯化生长和产酶条件优化,考察了白腐菌及其酶类对焦化废水的降解能力,结果表明:白腐菌在培养条件下能够产生白腐菌漆酶,是降解焦化废水中的多环芳香化合物的主要活性成分。经过白腐菌和活性污泥混合,得到较好的处理效果:实验时间内COD去除率达到89%,NH3-N达到88%,较单纯活性污泥效率高。     

Production and characterization of natural fiber‐reinforced thermoplastic composites using wheat straw modified with the fungus Pleurotus ostreatus

Wheat straw is an abundantly available and potentially valuable biomass that is currently under‐exploited. In this study, the feasibility of using wheat straw as a filler in high‐density polyethylene (HDPE)‐based composites was explored. Straw was treated with the white‐rot fungus Pleurotus ostreatus with the aim of improving adhesion between straw and plastic, and thereby the mechanical properties of the composite. Results indicate that the use of sterilized straw is necessary to inhibit the growth of indigenous organisms that preclude, likely through competition, removal of lignin, and hence, improved bonding between straw and plastic. Light and transmission electron microscopy revealed cell wall modification in sterilized, inoculated straw. Reduced thermal stability of treated straw did not negatively affect the production of injection‐molded straw–plastic composites (SPC). Comparable interfacial adhesion, based on activation energies obtained in dynamic mechanical analysis, was observed in untreated and treated straw‐ and pine‐based thermoplastic composites. The results of this study indicate that wheat straw represents a promising alternative to wood fillers in the production of thermoplastic composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5191–5201, 2006     

Degradation of wheat straw/polylactic acid composites with and without sodium alginate in natural soil and the effects on soil microorganisms

In order to improve the degradability of polylactic acid (PLA) composites and screen PLA degradation microorganisms. Sodium alginate was added into the wheat straw/PLA composites, and both composites (with/without sodium alginate) were buried in natural soil for 100 consecutive days subsequently. Weight loss and characterization of the PLA composites, carbon and nitrogen content in soil and microbial community composition were detected after degradation, with the result that the degradability of the PLA composites was greatly improved after the addition of sodium alginate. The weight loss of PLA composites with sodium alginate was 8.5%, which was 1.81 times that of PLA composites without sodium alginate. Sodium alginate and/or wheat straw in the PLA composites took the lead in the beginning course of the degradation. The added sodium alginate serves the purpose of making it easier to degrade the crystallization zone of the PLA composites. Bionectriaceae in the soil shoots up in the number after degradation, signifying its potential to be part of the microorganism family serving to degrade PLA composites. The results would help reveal the degradation mechanism of PLA composites and provide support for the screening of PLA composites degradation microorganisms.