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Mining of Novel Thermo-Stable Cellulolytic Genes from a Thermophilic Cellulose-Degrading Consortium by Metagenomics  [PDF]
Yu Xia, Feng Ju, Herbert H. P. Fang, Tong Zhang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053779
Abstract: In this study, metagenomics was applied to characterize the microbial community and to discover carbohydrate-active genes of an enriched thermophilic cellulose-degrading sludge. The 16S analysis showed that the sludge microbiome was dominated by genus of cellulolytic Clostridium and methanogenesis Methanothermobacter. In order to retrieve genes from the metagenome, de novo assembly of the 11,930,760 Illumina 100 bp paired-end reads (totally 1.2 Gb) was carried out. 75% of all reads was utilized in the de novo assembly. 31,499 ORFs (Open Reading Frame) with an average length of 852 bp were predicted from the assembly; and 64% of these ORFs were predicted to present full-length genes. Based on the Hidden Markol Model, 253 of the predicted thermo-stable genes were identified as putatively carbohydrate-active. Among them the relative dominance of GH9 (Glycoside Hydrolase) and corresponding CBM3 (Carbohydrate Binding Module) revealed a cellulosome-based attached metabolism of polysaccharide in the thermophilic sludge. The putative carbohydrate-active genes ranged from 20% to 100% amino acid sequence identity to known proteins in NCBI nr database, with half of them showed less than 50% similarity. In addition, the coverage of the genes (in terms of ORFs) identified in the sludge were developed into three clear trends (112×, 29× and 8×) in which 85% of the high coverage trend (112×) mainly consisted of phylum of Firmicutes while 49.3% of the 29× trend was affiliated to the phylum of Chloroflexi.
Coculture fermentation of banana agro-waste to ethanol by cellulolytic thermophilic Clostridium thermocellum CT2
KRY Harish, M Srijana, RD Madhusudhan, Reddy Gopal
African Journal of Biotechnology , 2010,
Abstract: Banana is a major cash crop of many regions generating good amount of waste after harvest. This agro waste which is left for natural degradation is used as substrate for single step ethanol fermentation by thermophilic, cellulolytic, ethanologenic Clostridium thermocellum CT2, a new culture isolated from elephant droppings. Scanning electron microscopic pictures clearly indicate cellulolysis and close interaction of selected isolate CT2 with cellulose. The optimum conditions for cellulose fermentation were 60°C, pH 7.5, inoculums size 5% and incubation time 5 days. Ethanol produced and reducing sugars were estimated by gas chromatography. Clostridium thermosaccharolyticum HG8 and Thermoanaerobacter ethanolicus ATCC 31937 were used in coculture fermentation with CT2. Coculture fermentation of CT2 with HG8 was more efficient in terms of ethanol production, cellulose degradation and reducing sugars utilization. A maximum ethanol yield of 0.41g/g substrate used was obtained on coculturing CT2 with HG8 on alkali treated banana waste. Coculture was active even at substrate concentrations up to 100 g/l, a maximum ethanol of 22 g/l was obtained at 100 g/l substrate concentration on coculturing CT2 with HG8. This is the first report on anaerobic single step conversion of banana waste to ethanol by C. thermocellum.
Isolation, Identification and Phylogenetic Analysis of A Thermophilic Cellulolytic Anaerobic Bacterium
嗜热厌氧纤维素降解细菌的分离、鉴定及其系统发育分析

Han Ruyang Min Hang Che Meici Zhao Yuhua,
韩如旸
,闵航,陈美慈,赵宇华

微生物学报 , 2002,
Abstract: Four strains of thermophilic cellulolytic anaeobic bacteria were isolated from fresh feces, heat compost, cellulolytic mixed culture with a method based on adherence of cellulolytic bacteria to cellulose. The cells of isolates were straight or slightly curved rods that were 0.4 micron-0.6 micron x 3 microns-15 microns, Gram negative, strictly anaerobic, sulfate reduction negative, spore-forming bacteria. Most of the cells had oval terminal spores, while subterminal spores, middle spores, two or more spores also could be observed and spore formation could occurred in any position. The isolates degraded cellulose filter paper, cellulose powder Whatman CF II, microcrystalline cellulose, cellulose powder MN300 and unpretreated maize stem core, sugarcane residue and rice straw. The pH and temperature ranges for growth on cellulose were 6.2-8.9 and 45 degrees C-65 degrees C respectively with the optima, 7.0-7.5 and 55 degrees C-60 degrees C, respectively. The major fermentation products from cellulose were acetic acid, ethanol, CO2, H2. The isolates could ferment cellobiose, glucose, fructose, maltose, and sorbital. The phylogenetic analysis based on 16S rDNA suggested strain EVA1 was the closest relative of Clostridium thermocellum with 99.8% sequence similarity.
Degradation of Phenolic Compounds in Creosote Treated Wood Waste by A Mixed Microbial Culture Augmented with Cellulolytic- Thermophilic Actinomaycets Thermobifida fusca  [PDF]
Abdel E Ghaly, Bopeng Zhang, Deepika Dave
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.31011
Abstract: Creosote is used for preservation of railway ties and timbers, electric utility poles, marine and foundation piling, fences and garden furniture. Creosote-treated wood waste may cause potential contamination of soil and water if they are not disposed properly. Creosote contains over 300 organic compounds including polycyclic aromatic hydrocarbons, phenolic compounds and heterocyclic organic compounds, many of which are toxic to human and can cause damage to kidney, liver, eyes and skin. The feasibility of using a composting technique inoculated with the cellulose degrading actinomycetesThermobifidafusca as a mesophilic/thermophilic bioremediation option to degrade phenolic compounds in creosote treated wood waste was evaluated. The temperature profile of bioremediation process clearly identified mesophilic and thermophilic phases in both experiments. Different degradation rates were observed in the mesophilic and thermophilic phases. Fluctuations of pH was observed in both experiment as the result of the breakdown of organic nitrogen to ammonium in the first week and the formation of organic acids and the loss of ammonium with the exhaust gases in the latter stage. The moisture content decreased in both trials because of the net loss of water with the exhaust gas. Both experiments achieved similar reductions in total carbon and TKN, volatile solids and phenolic compounds, cellulose and lignin indicating similar levels of microbial activities during the composting process. The stability and maturity of the final products were also similar. The inoculation of the cellulolytic-thermophilicactinomycetesThermobifidafusca did not manifest observable differences in degrading cellulose, lignin and phenolic compounds compared with the control.
棉纤维原纤结构的分形特征  [PDF]
万广兰,于伟东
纺织学报 , 2011,
Abstract: 棉纤维各层结构中的原纤堆砌形式早期受到众多的关注,有多种多级原纤体的模型。本文着重棉纤维次生层S2的分形特征,假设了四级原纤体堆砌成的三级分形结构,采用三种不同形式的原纤堆砌模型——圆形、混杂型和椭圆形,对其进行了各级原纤半径、分维数和结晶度的估算与对比分析,对存在的差异作了模型修正验算。结果证明椭圆形模型的修正模型,其三级分维数分别为1.6575、1.647和1.732,其修正的原纤束结晶度为64.7%,与棉纤维实际结晶度66.7%相近。
经分纤处理蚕丝纤维的微孔填埋特性研究  [PDF]
纺织学报 , 2004,
Abstract: 采用锡酸增重法来表征蚕丝纤维内部微孔,比较普通蚕丝纤维与分纤蚕丝纤维经锡酸填埋后的微观形态特征。结果表明,蚕丝纤维经分纤处理后填埋锡酸胶体的能力提高,且其填埋能力随分纤处理时间的延长而增加,证明蚕丝纤维经分纤处理后内部结构变得松散,有微孔生成。
Effect of Carbon and Nitrogen Sources on the Production of Reducing Sugars, Extra-cellular Protein and Cellulolytic Enzymes by Two Cellulolytic Bacterial Isolates  [PDF]
M.A. Kashem,M.A. Manchur,M.S. Rahman,M.N. Anwar
Pakistan Journal of Biological Sciences , 2004,
Abstract: Two thermophilic cellulolytic bacterial isolates were tested to determine the effect of carbon and nitrogen sources on the production of extra-cellular proteins, reducing sugars and cellulolytic enzymes. Lactose was found to be the most potential carbon source for Avicelase (342.52 U mL-1) and -glucosidase (256.89 U mL-1) activity where as NH4Cl was found to be the potential nitrogen source for CMCase (144.68 U mL-1) activity.
王鉴绘画思想探微  [PDF]
张俊,赵启斌
东南文化 , 2003,
Abstract: ????王鉴为明末清初的四王之一,一生致力于宋元诸家的临仿创承。由于王鉴的家世及他在明末清初的特殊环境中所处的位置,以及其处于董其昌和王原祁、王之间的特殊地位,绘画的价值取向对四王风格的整体构成,占有十分重要的地位。
对鉴证准则增加“鉴证对象”的思考  [PDF]
林清林,宋刚
财会月刊 , 2006,
Abstract: 在鉴证实务中,一直存在着在法律上无法对鉴证对象进行明确界定的问题,而套用审计准则来界定在范围上又显得过于狭窄,这一直是影响注册会计师开展鉴证业务的一个重要因素。本文从分析鉴证与审计的区别开始,探讨了鉴证准则增加“鉴证对象”的动因以及影响。【关键词】鉴证准则鉴证对象动因影响将于2007年1月1日起施行的《中国注册会计师鉴证业务基本准则》(简称“鉴证准则”)的第五章增加了“鉴证对象”的相关内容。鉴证准则第五章第二十一条规定,鉴证对象主要分为财务业绩或状况、非财务业绩或状况、物理特征、某种系统和过程、行为五大类,而与这五类鉴证对象相对应的信息形式分别为财务报表、反映效率或效果的关键指标、有关鉴证对象物理特征的说明文件、关于系统和过程有效性的认定、对法律法规遵守情况或执行效果的声明。
试论合同鉴证  [PDF]
黎晓宽
法学研究 , 1981,
Abstract: 目前,在国民经济调整和经济体制改革中,各地大都在推行经济合同制度,逐步加强合同管理工作。在合同管理工作中要不要包括合同鉴证这项内容,这是正在讨论的问题。认真研究并解决这个问题,既是实际工作和经济合同立法工作的需要,也具有一定的理论意义。一、合同鉴证的产生和发展合同鉴证在我国产生于五十年代初期。当时,国家采用加工订货、经销代销等形式,对资本主义工商业进行限制、利用和改造。
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